Best Buy HSBC Retail Service never sent bill, paid amount due, they continued charging financial fees for 6 month, never contacting us, then secretely sent to collections. Internet

Purchased an AC unit from Best buy. We received 1 bill, made the first payment and then never received a second bill. Made the payment of what was believed to be the final amount, but there was a finance charge that we were unaware of. Believing the charge was paid for we never looked back until 7 months later we ran a credit check and discovered that our account had been sent to collections by HSBC. We were surprised that we never received a phone call or any other notification from either party after that first bill. We contacted the credit agency and paid their amount due before contacting both parties. Best buy was more than willing to give us a gift card for the amount of the charge, and contacted HSBC which they discovered were at fault. HSBC was not willing to help us. All we wanted was for them to write a letter and have our credit repaired, which they refused to do. We had our credit ruined for a $15 late fee.