Product: Debt collection

I had an outstanding medical bill of {$790.00} that was sent to collection with Merchants CR. I called them on XX/XX/XXXX to pay this bill and the representative I spoke to told me that XXXX ( who the medical bill was from ) was offering me a settlement for {$600.00} so long as I paid it within 30 days. I agreed and set up a payment plan of three payments of {$200.00} using my credit card. The first payment was charged to my credit card on XX/XX/XXXX, the day that I set up the payment plan. The second payment was charged to my credit card on XX/XX/XXXX and the third was charged on XX/XX/XXXX. However, on XX/XX/XXXX I called Merchant about a different medical bill that I had paid through the doctors office to see if it had come out of my account and while we were on the phone, the representative I was speaking to mentioned that I still had an outstanding balance of {$790.00} from XXXX. I told him that I had already set up a payment plan and that {$400.00} had already been charged to my credit card. He had no record of this anywhere and I ended up having to fax them a copy of my credit card statement to prove that the money came out. It took them until Friday the XXXX to finally resolve the issue. The woman I set up the payment plan with had applied my money to someone else 's account, but they didn't know whose so essentially they lost my money and their accountant had to go and find it. When they called to tell me that they had located my {$400.00} and applied it to my account, I mentioned that I still had another payment of {$200.00} that was scheduled for XX/XX/XXXX and asked if this was going to be applied to my account or if it was still set up to be applied to someone else 's account. They assured me that they fixed everything and that the final payment would be applied to my account and then also told me that I owed another {$36.00} because the settlement was actually for {$630.00} even though the woman I spoke to told me it was only for {$600.00}. I disputed this and told them that the woman set the payment plan up for {$600.00} and that is the amount I agreed on, therefore that is the amount I'm going to pay. They said that was fine and that they'd take off the {$36.00}. Fast forward to last Friday, XX/XX/XXXX. I called them just to make sure everything was good to go and that my balance was settled. They told me that I still owe {$230.00}. I told them that we had already disputed the extra {$36.00} and that the last {$200.00} had already come out of my account XX/XX/XXXX. They said they have no idea where the last {$200.00} is and assured me they would fix it and asked me to give them a call a back Monday or Tuesday. I just got off the phone with them and when I called they said the same thing : " The {$400.00} we received for your account, but it looks like you still owe {$230.00} ''. It was like the person I spoke to Friday had no recollection of the conversation we had just had. He'd done nothing to try and fix the issue and told me he has no idea how this happened and that his accountant who was able to find and apply the first {$400.00} to my account is out on vacation. This has been going on for over a month now. I've had to take time out of my day at work to call them several times because they keep losing my money. If I hadn't called them last Friday to check and see that all my accounts were paid off, they still would've had me owing {$230.00} to them that I do not owe. No one there seems to know what's going on and none of them seem to know how to fix this issue. Every time I think that it's finally fixed, it turns out that it isn't. I do not trust this company with my money. I still have no idea where my last {$200.00} is and it has been a huge stressful hassle to figure out where the first {$400.00} went.