Product: Credit card or prepaid card

In mid XX/XX/XXXX I reported my Synchrony Car Care card lost. Upon doing that I was told that I would be sent a new card. Weeks went by ... no card. So I logged in on XX/XX/XXXX and scheduled my monthly payment for XX/XX/XXXX ( due date ). 
XX/XX/XXXX I still had not received a card and my account was no longer accessible online. I called rep and she said a new card had just been issued and made it so that I was able to set up the new account online. XX/XX/XXXX my payment had not posted to my account, so I contacted Synchrony via their message portal to have record of our conversation. I asked them where my payment was and gave them confirmation #. They replied that it takes 2 business days to process & post. I gave them 5 days before I contacted again. Payment had not posted nor had it been deducted from bank account. I asked them to credit my account for the payment and deal with finding the actual payment later since we were both in agreement that the payment had been made via the confirmation #. 
They contacted me 2 days later and said " As per your request, our records indicate that an online payment of {$27.00} was cancelled on your account for XX/XX/2018. '' I informed them that I NEVER asked them to cancel a payment ... I asked them to credit my payment and they have the messages there to prove I NEVER requested that. They in turn contacted me 3 days after ( XX/XX/XXXX )  I messaged them this and stated that they had confirmation # for cancellation and they would reverse the late payment fee. 
Since I found out that day that they cancelled my payment, I made them aware that I was making my payment the same day. 
After I contacted them on XX/XX/XXXX again, I logged in to new account to make payment, once logged in I noticed that they doubled my payment due to {$46.00} because of the late fee. Once I contacted them about this they said " Our records indicate that the payment of {$27.00} was not paid by XX/XX/2018. Please note that the minimum payment due will increase on your account when there is a late payment. The minimum payment due is around 3.5 % of the balance, plus the late fee, plus the interest charge, plus the past due amount. '' The payment was late because THEY cancelled it!! I asked them to reduce minimum due to what it should be but now they won't reduce it to the correct amount. They keep saying I made my payment late! 
I have been back and forth with them up until today. I even spoke to a manage who kept telling me that I logged in and cancelled the payment myself after I kept telling her I didn't. Why would I cancel payment if I didn't have access to old account to log in and cancel ... .and additionally why would I cancel payment if I'm asking you to credit the payment and find it since it already has a confirmation #. It didn't make sense what she was telling me. In customer service pattern after I asked her to stop over talking me and actually listen, she hung up on me. I called back and the new rep said there was no other manager to speak to, there was no one over the manager that hung up on me to speak to and she couldn't do anything because the manager that had hung up on me noted my account ( it's XXXX ... how is she already gone for the day? That was a lie ) that no one could make any adjustments and left for the day. 
I have proof that I did not request my payment to be cancelled. I have proof that Synchrony did that on their own because they sent me email notification that they cancelled it because my account had a balance of 'XXXX '. Which led me to believe that when they opened my new account, my payment was there but instead of letting it sit and wait for the balance from the old account to be transferred over, they cancelled my payment and now are placing blame on me and penalizing me. My minimum due should be $ XXXX- {$27.00}. I have currently been out of work and trying to make my payments on time. The minimum due is what I budgeted for but yet the doubled my payment on me through no fault of mines but are placing fault on me and won't reduce it or adjust it.Saying because statement has already been generated they can't do anything. I've gotten so many different excuses as to why they can't fix their mistake that its crazy. 
If I make a mistake or am late, I will be the first to admit, but in this case it was NOT me!!