Audi not taking my debit order instead harassing me with calls about debit order not going through

I sent Audi Financial service my changed banking details two months back(March 2021) and till date, my April debit order has not changed instead they keep calling me telling me that I owe on my vehicle but they refuse to take the money in my account and I believe they will want to make me pay for interest on a fault that belongs to them. The worst decision was signing that contract with Audi financial services and not going with a different financial institution.