RTG Synchrony Bank review: Unauthorized credit card charges

In April 2021 I purchased a mattress with my RTG Synchrony Bank credit card. At that time, Synchrony Bank signed me up for a 24-month no-interest payment plan on my purchase. I made arrangements with my bank to make recurring equal monthly payments to Synchrony Bank for 24 months to pay off my account. All my payments were made on time. In March 2022, I started receiving notices from Synchrony Bank that I owed unpaid interest on my account. When I contacted customer service, no one could explain why they were charging me the interest. My 24-month pay-off date was April 2023. I demanded to speak to someone who could explain the charges. Instead, the person I was speaking with cut me off and redirected my call to an automated voice system that prompted me to make an interest payment to my account! The next day I made arrangements with my bank to pay off my Synchrony account in full. No more fraudulent charges. I cut up my RTG card and will never do business with Synchrony Bank again.