Fees or interest: Credit card

I am filing a formal dispute against Synchrony Bank regarding an unfair and deceptive billing practice involving deferred promotional interest. I purchased a couch under an interest-free promotional period. To ensure the account was handled responsibly, I enrolled in Synchronys automated payment ( Auto-Pay ) feature.I was under the clear impression that enrolling in Auto-Pay on a promotional account would structure the monthly payments to successfully clear the principal balance before the promotional expiration date. Instead, Synchrony 's system defaulted my automated payments to a minimum amount calculated to leave a remaining balance of $1500.00 at the deadline. Because of this structural system design, I was hit with a retroactive, deferred interest penalty of $ XXXXSynchrony 's online portal user interface is intentionally designed to induce a promotional default by failing to align automated payments with the actual promotional timeline. I have maintained a flawless payment history on this account. I have now paid off the remaining $1500.00 principal balance in full.As a consumer, I acted in good faith by setting up automated payments. Synchrony 's refusal to offer a one-time courtesy waiver for an automated system oversight is predatory. I am requesting that Synchrony Bank escalate this to their executive consumer care team to waive and credit back the $2000.00 deferred interest charge.