Disastrous service and unauthorized debits

I have contacted gym company numerous times to discuss my contract that ended in March with them. They have been of no assistance in cancelling the contract but instead continue with debit orders even when it’s ended, they have also been of no assistance when I have requested to discuss payment arrangements for the arrears I have been advised I have acquired. They also refused to use the debit orders as a form of payment for the arrears even after my contract ended, no alternative methods are provided to cancellation, I have asked them to do it over the phone or provide me with an email address to submit my formal cancellation the receptionist at Maponya mall advised they do not have one.

I am exhausted and I want my relationship with them to be over