Product: Credit card or prepaid card

On XX/XX/XXXX I was approved for an Avant Master Card Credit card issued by XXXX of XXXX XXXX XXXX, UT On XX/XX/XXXX I scheduled a payment for the entire balance to post the same day I haf a little difficulty setting up first payment, entering new payment information but it allowed me to proceed so I thought everything was set. 
On XX/XX/XXXX I received an email with headline " Your payment has been received '' On XX/XX/XXXX I received an email stating " Upgrade your Bank Account Today '' This was a generic headline and I thought it was a marketing email, not an issue with my bank account so I didn't open it. It did not state " '' Payment Has Not Been Received '' or something more clear, On XX/XX/XXXX I received an email stating that Payment Has Not been Received. A late fee + interest charges were applied to my account on XX/XX/XXXX On XX/XX/XXXX after realizing payment did not go through, I logged in and updated my payment information On XX/XX/XXXX ( approximately ) I called and explained to them that I did try to make a payment but had issues and didn't realize it did not go through until the XX/XX/XXXX email and that their XX/XX/XXXX email was unclear. They said over the phone that they could not reverse the late fee and that I would have to submit an online request. So I did and on XX/XX/XXXX they responded rejecting my request. 
On XX/XX/XXXX I appealed this request On XX/XX/XXXX my appeal was rejected Not sure of exact date but I appealed a third time after XX/XX/XXXX On XX/XX/XXXX this too was rejected On XX/XX/XXXX My statement posted. I was charged interest either on top of interest and/or the late fee On XX/XX/XXXX My new statement posted and there was a charge for {$1.00} interest and a {$26.00} late fee charge. 
on XX/XX/XXXX I went to use the card to place a deposit on a car rental and had to call Avant as card was not working. The representative of Avant said I had to make a payment equal to the late fee in order for the card to be used. Because I was not finished disputing the late fees, I did not want to pay more than I had to. So I made a payment of {$26.00}. I asked if I would be charged any additional fees if I did not pay full balance. The representative clearly said I would not. 
I contacted them again protesting the late charge and asking for it to be reversed and again I was rejected. I told them what the representative had said and asked them to listen to the recording as it says when you call that all calls are recorded. This would prove that I was not making it up. 
On XX/XX/XXXX this was their reply via email " We are sorry for any misunderstanding that may have occurred during your customer service experience. However, during our review of your account, we have been unable to substantiate your claim. '' On XX/XX/XXXX I was charged another late fee even though I made a payment and even though the representative said I would not be charged any fees. 
So no new purchases were made since XXXX and I paid that balance in XXXX and even paid one of the late fees in XXXX yet I have been charged close to {$100.00} in fees and interest. 
ON XX/XX/XXXX I asked for call transcripts since they said they were unable to substantiate my claim from XX/XX/XXXX. 
I tried explaining to them initially that it was a new account and that it was difficult to see what account information you were entering because due to privacy protection, you can't see the numbers, just a star where the number should be. It doesn't make sense that I would sign up for a brand new card where an initial fee is required and then make a false payment. 
Other than the transaction in XXXX, no additional purchases were made using this card. If their initial email notifying me that the bank account info was wrong was clear, none of this would have happened. If they had understood the error involved with the initial payment and reversed the late fee, I wouldn't be wasting precious time writing this email. It doesn't appear they even bothered to read any of the appeals to reverse the late fee and just rejected it automatically, without consideration.