Discord won't refund me my money for nitro

I acccidentaly forgot to cancel my nitro and discoord wont respond,to my luck it's not paid alredy because it's in my reservations (debit card), so what is the next step? Contact bank and block the payment or try to negotiate with discord to not bill me anything, I've alredy canceld future payments to nitro but that didn't block the reservation for this payment. Anything helps!