Product: Credit card or prepaid card

I purchased a mattress from XXXX XXXX in XX/XX/XXXX, to be delivered in XX/XX/XXXX. At that time, I also bought a mattress pad and pillow. I opened a store card so that I would be able to pay for my purchases, interest-free, over a 3-year period.Due to issues with my living situation, I had the delivery of my mattress delayed until I was ready to move. However, the mattress pad and pillow purchases showed up on the credit card on the date that the items were originally supposed to be delivered. I did not know what this amount was for, as I had no actual purchase on that date, and thought there had been fraudulent activity. So, I had the account shut down, and XXXX XXXX, the bank for the XXXX XXXX credit card, issued me a new account. I later realized what had happened and paid the charge in full. However, because the bank never sent me a statement with the new account number, I didn't initially realize I had to pay. I called the bank (without having received a statement, but wondering about it) and was told the payment was late, but they reversed the late fee since I had not received a statement with the correct, new account number.After the mattress was delivered (XX/XX/XXXX) and I began receiving statements for that, I paid on time each month. The minimum due is $XXXX/month, and I pay $XXXX each month. I use the bill-pay option with my bank, and have the NEW account number attached to the payment. On XX/XX/XXXX, I received an email from XXXX XXXX saying that I was delinquent with my payment, and that I should call as my account was past due, even though I had made my payment on time. I spoke to XXXX on XX/XX/XXXX, who told me that the payment had not gone through and said I needed to contact my bank, as they were the ones who had denied the payment. (He saw that the payment was made on XX/XX/XXXX, but said that the payment did not go through.) I told him this was not true--I had plenty of funds to cover the payment, and in fact the payment had been debited from my account. He asked if I could fax them a copy of my statement showing that the funds had been debited from my account. I did fax a copy on XX/XX/XXXX, showing that the money from my account had been removed and paid to XXXX XXXX.I called again on XX/XX/XXXX and spoke to XX/XX/XXXXXX/XX/XXXX. He did not seem to have a record of the fax I had sent the prior week. However, he said that it looked like my payments were going to the defunct account (the one that had been closed when I thought there was fraudulent activity). I said that made no sense--there is no balance on that account, and I was sending payments to the other one. He said that he would make a note of my complaint, and that it would be looked into. I asked when this would be taken care of--he said he could not transfer the money from the incorrect account to the correct one himself--and he said to call back in a week. XXXX. XXXX was very difficult to understand and the nature of the call was very frustrating.Throughout all this time, I keep getting emails from XXXX XXXX  saying that I have not paid, even though I have and have been trying to take care of the situation.I called again on XX/XX/XXXX and refused to speak to the person answering the phone, saying I would like to speak to a supervisor. I was transferred to XXXX. I explained what had been happening, and she said that she had a record of my calls, and that it was being looked into and that the problem should be resolved. I told her I was getting emails saying I was delinquent and she said to ignore them, that they are just generated by the system. She also said I could follow-up again the next week. She said I might be paying the wrong account. I insisted I had the correct number of the 2nd account, but said I would double check just in case. (I did double check and indeed the correct account number was attached to the bank payments.)The following week, on XX/XX/XXXX, I received a call from XXXX XXXX (I did not get the person's name). The man said that he was calling to follow up on my concerns. He made sure that he understood what had been happening, and said that he was going to be transferring the now $XXXX credit ($XXXX for each of 3 months) that had gone to the incorrect account, to the correct account. I said that I thought this was already being taken care of, but he said he would be the person doing the transfer. I assumed the problem was finally being taken care of.OnXX/XX/XXXX, I received an email from XXXX XXXX (I have an account with them) saying my credit score had gone down. I have excellent credit, and the only reason this could have happened is because of the problems with XXXX XXXX.On XX/XX/XXXX, I received a check in the mail for $XXXX. Instead of crediting the 3 months of payments I had made by transferring the $XXXX as they had said they would do to the correct account, XXXX XXXX instead returned those payments to me. They then turned my account over to a collection agency. On XX/XX/XXXX, I received an email saying that my account had been turned over to XXXX XXXX XXXX, and that I should call them about the account. As I had had the $XXXX in payments returned to me, I understood that this was now a collection agency, and that I'd better pay again as they now did not have the $XXXX in payments I had made.On XX/XX/XXXX, I called XXXX XXXX and they verified that they are a collection agency. I spoke to XXXX XXXX and told her what had happened, and said that I would pay the $XXXX since it had erroneously been sent back to me. She listened to my story and was concerned, so she offered to pass me to a supervisor. I then spoke to XXXX XXXX, who simply collected my $XXXX payment. The total bill was $XXXX, and I felt that this extra amount was a late charge. I told her I would not pay the late charge as I have never been late with my payment. I then tried calling XXXX XXXX to follow up with them about what had been happening (still on XX/XX/XXXX). It took me FIVE TIMES to be able to get through to them. The first time, after I entered in my account number, the system hung up on me. The second time, the call got pushed through to the collection agency, and I thought I had dialed the wrong number. The third time, after entering my account information, the system hung up on me AGAIN. Specifically, both times, the automated system said, "Your call cannot be transferred" and the system disconnected. I called a 4th time and it happened AGAIN. The 5th time, I called from a blocked number, and pretended I didn't know my account number. Only because of this, I was able to be transferred to a XXXX XXXX employee.I spoke to XXXX, who said that she could not remove the late fee. So, I asked to speak to a supervisor, and spoke to XXXX. She also told me that she could not remove the late fee because they had done so earlier in the year, and do not do so more than once per year. (The first time was when they had not sent me a statement with the new account number.) She said that a formal complaint was filed on my behalf on XX/XX/XXXX, and that they won't credit the late fee until the complaint is resolved. She said if they saw that I was making payments on time, they would likely reverse the late fee. I asked when the complaint would be resolved, and she said within 30 days. I said it had been over 30 days, so I would like an answer, and she then said that it would be resolved within 30 days OR MORE. I commented that it seems as if this could just go on without an end in sight, and she suggested I call back in the next week. We discussed the fact that the $XXXX was due by XX/XX/XXXX, and since I would be paying my next monthly installment of $XXXX, that would be added to the already-paid $XXXX, and so I should not get another late fee as the upcoming $XXXX payment would more than cover the rest.On XX/XX/XXXX, I received a certified letter from XXXX XXXX, dated XX/XX/XXXX, saying my account was going to collections.On XXXX, my bank sent my next $XXXX payment to XXXX XXXX  (payments are due the 10th of the month). I realized I was likely to have a problem with that payment not going through, so I decided to go to the XXXX XXXX website (mysynchrony.com) and make a payment directly to them. I did so for $XXXX. However, I am concerned that it showed me still owing $XXXX on my account, even though I had paid $XXXX of that 6 days earlier directly to the collection agency. That XXXX had been debited from my bank account that same day.For the current month, I have now paid $XXXX total--$XXXX to the collection agency, and another $XXXX in two separate $XXXX payments. Today, XX/XX/XXXX, when I went to their website, it only shows the $XXXX credit done through their website, and says I still owe $XXXX, which I do not. I am worried that they will now charge me more late fees, even though I have significantly overpaid what is actually due.