Product: Credit card or prepaid card

We have a XXXX XXXX XXXX Account with a promotional rate. As such, I try to be careful to pay more than minimum and early. I have had a couple times where I thought I was paid a month ahead and received a late fee, but things happen and I didn't complain. Then on XX/XX/XXXX, the primary on the account received a 'Collections ' call. The person calling stated that we hadn't made a payment since XXXX and she wanted to help us figure out our account. My husband called me wondering what happened and I called the company to straighten it out. On XX/XX/XXXX, I called the customer service number on our statement. I told the person that called that I had made a Payment on XX/XX/XXXX and another on XX/XX/XXXX ; my records indicated that I was not due until XX/XX/2021. The person confirmed the payments posted on the days mentioned. I stated, " oh, you must have a cycle thing that won't advance the due date. I will need to get that cycle date so that I can be sure to wait for them in the future. '' Then asked him to repost the last payment and remove the late charge. He told me that he could remove the late fee as a 'one time courtesy credit ' AFTER I paid the past due balance. I got angry and said 'what past due amount, you just confirmed 2 payments posted. ' He stated the I had to pay the past due of {$1300.00} ; when I persisted with where that number came from I was told, $ xxx for XXXX and $ XXXX for XXXX and the late fee. I said are you joking, you want me to pre-pay my account before you will fix a posting error? This went back and forth a couple times then I asked to speak to a supervisor. He stated " I will transfer you to a supervisor so she can tell you the same thing. ". Not terribly professional or friendly, but these things happen. The supervisor was possibly more unprofessional and stated that she wouldn't re-post anything and she might refund the late fee after I paid the {$1300.00}. I told her I was NOT pre-paying my account, but I was getting ready to make a payment in the next couple days so I would make a payment so they could take care of the late fee. A couple days later my bill came in ; it reflected the next due as XX/XX/XXXX and a late fee assessed on XX/XX/XXXX! I then decided to post a complaint on their web-site thinking that the management level would care. This email went out on the evening of XX/XX/XXXX. I received auto responses from the ombudsman email and the customer care email. I did receive a call on the afternoon of XX/XX/XXXX, the customer service person calling did not speak clearly and I couldn't understand her name. I returned a call to the customer service, the same that I started with, and asked what the other person was calling about or if they could put me in contact with that person. I was told she was calling to tell me that she was going to give me a " one-time courtesy credit '' of the late fee. I advised that wasn't good enough, I want my payment history reviewed and properly applied. I want previous late fees reversed if I was not actually late. It was never disclosed that I needed to make a payment every calendar month. Nor was I made aware that there was a billing cycle to work around. I simply want the company to properly post the payments that I have made and advise me of the cycle date, so that I can be sure to send payments after that date in the future. It think it is sad that I had to resort to this. I can provide a copy of the email sent to the company.