Debt collection complaint — Unknown

I had XXXX XXXX done last year and took advantage of zero interest for 12 months which was due to expire XX/XX/2020. My wife scheduled the final payment of {$570.00} through our credit union on XX/XX/2020 to be paid XX/XX/XXXX. The payment was processed and reached Comenity - XXXX XXXX XXXXXXXX XXXX XXXX of XX/XX/XXXX. I received a bill for {$480.00} for interest charges.