Refusal to cancel debit order

I opened a new 8TA contract in November. The first two months they processed the debit on the incorrect bank account. Then in January it was done correctly. February it was never processed!! AND to add insult to the injury my credit report now shows I am a slow payer because 8TA does not know how to process a debit order correctly. I then phoned the call center (Anastasia) and requested that they cancel the debit order, but she refused. So they can not do their jobs but refuse to cancel debit order??