CareCredit review: Care credit closed account 1

I opened a Care Credit account in 2020. I had surgery and was paying it back and have never been late. In September I had a dental emergency and used the card with deferred interest for a year. I wanted to know how that works since I noticed you could not separate payments for the two Care Credit accounts. One person told me that they could not allocate payment and another told me that when I make a payment that it would pay the first of 313 and the 170 would go to the dental and to do it online. So last week I went on line to pay, and the website said that it did not go through try again, so I did and it again said it did not go through so I did it again and it said it did not go through. I called the automated and made a payment on the phone. Then I checked the account and saw that I had several payments processing and called and was told that it had to go through and that once they did they would send me a check for the over payment. I didn't want that much money taken out of my account so I put a stop payment with my bank. Today I took that stop payment off and called Care Credit/Synchrony bank to get a payment allocated and found out that my account is closed. I had never been late, all kinds of notes were in my account from the MANY times I spoke with their reps. The rep told me that it was because of the stop payment. I'm so frustrated. I didn't want to wait for them to mail me a check because the rep told me it takes a while. The closing of the account is automated so there is no reversing. Their website malfunctioned and now I'm penalized. I heard so many different stories on how to deal with my account and trying to make the payments on the two transactions from the reps. They are not consumer friendly and my credit will take a hit because of this situation. I'm so FRUSTRATED!