Synchrony Financial Credit Card Complaint

Synchrony Financial Credit card department,

Payoff process Florida

Went to - and purchased a bedroom set with their 12 mo same as cash deal though Synchrony Bank. I made equal payments on time each month and payed off the original amount of $2300.00. The following month they send a bill for $800.00 plus and for the 33 % interest plus Card Security charges and late fees. I never authorized any card security protection. I feel this is a scam against consumers and want this account cleared of all interest, card protection and late charges. Thank you