Synchrony Bank Credit Card Complaint

Synchrony Bank Credit card department,

Late fee Arizona

Paid off credit card with Synchrony Bank during the promotional period. This amount covered the amount that was used to make purchases. I told the company to close my card, which they did. 2 weeks later I received a bill in the mail that I still owe another $290.00. I called Synchrony Bank and they told me I owe $290.00 in late fees. I asked them how when I paid each month on the credit card. It is also listed on my credit report that I paid on time every month. The company for some reason, will not remove the late fees, even though I was never late ... They have now charged me another late fee and the balance is over $300.00. I made numerous attempts to call them and tell them I do not owe them a late fee if I was never late on payments and have proof from the credit bureaus that it was reported on time.