Product: Credit card or prepaid card

I was approved for a XXXX XXXX XXXX in XXXX. I made a few purchases and promptly made 2 payments on the account to keep the balance down since I was planning to use this card mainly for an auto pay medical bill. These payments were posted and credited to my account promptly. I set the auto pay up to start on XX/XX/XXXX. I made a {$350.00} payment on this account on XX/XX/XXXX to ensure that enough credit was available to cover the auto pay bill. Unfortunately my bill was not paid because a payment hold was put on the credit card account and didn't get released until after the XXXX of XXXX, even though I paid the account on XX/XX/XXXX. I was also charged a {$25.00} failure to process fee for the auto pay bill. I called customer service and it was explained to me that payment holds can happen to accounts under 6 months old and that it would not happen again once one payment had been put on hold. I made an additional payment of {$50.00} to more than cover the failure to process fee. On XX/XX/XXXX, I made a {$400.00} payment to the account to ensure that enough credit was applied to cover the auto pay bill and to reduce the remaining balance on the card. The payment was removed from bank account and shown to be made on the account but was not applied. I called customer service today, XX/XX/XXXX, to see why credit was not applied even though payment has processed and when it would be applied. Customer service told me my payment had been put on hold and credit would not be applied until the XXXX or XXXX. I relayed that the previous time this happened I was told that it would not happen again, and was informed that I was lied to by the previous agent. I asked if the hold could be removed and was told no. I asked if I could be reimbursed for the failure to process fee, since that wasn't my fault, and was told no, not their problem, you really just got screwed and there is nothing we can do. I asked to speak to somebody higher up and was transferred. The next CSR I spoke with told me that every payment I make is subject to a hold and it can not be removed and the failure to process fee is not their responsibility ( I honestly didn't expect to be, but why not try ). I asked for a credit increase ( didn't expect it, but again why not try ) and was told no. I was told there was nothing they could do to get the payment hold off, apply credit to my account and that my next payments could be put on hold as well. Even though the fine print in the account statement says that credit for payments will be applied by the next day or may be delayed up to 5 days. Not delayed for 15 plus days. I get it for one payment to be put on hold, but multiple is absurd. I didn't max the card out, I made multiple payments before the due date even and made them well in advance of when a charge to the account was to be made. As a single mother, working full time, I can not afford to have holds put on accounts and pay extra for failure to process fess when I made my payments. I can not let this auto pay bill be late again, so now I have to juggle my other bills just to be able to pay a bill that I shouldn't have to worry about. I was hoping to use this card to help build my credit but this has done nothing but damage my credit and create more stress than was needed.