Bad attitude/Poor customer service and disrespectful consultant

I have made arrangement on the nimble group app, and they have been debiting my account, only now in December I have change arrangement, now I am being harrased with calls by Norman bissets consultant, they say they are still going to harass me until I approve Debi check. I ask how can you force me to approve Debi check on account that was opened before Debi check was in troduced? The consultant told me that this money that they want from me they are not borrowing it they want it because it belongs to them I need to pay and they are still going to harras me and they will put charges on call that they call me. First I made arrangement and they are debiting but I am being harrased vto change debit order to a Debi check which I don't want. The consultant continue to shout at me until he drop the line. Am paying account am being shouted for Debi check. Norman bissets is saying they are not borrowing the money from me they want the money, is debicheck the money? Because as for the money am paying.