Bad customer service

I joined the gym in October, and my 1st debit order was supposed to go off on the 15th on November as I requested. They tried debiting my account even after I told them that I will be paying on the 15th of every month they still went in to debit messing up my personal account with unpaid debit and charges , since I joined the gym I have been blocked and they would unblock me for a week and block me again saying I owe them, I called collections department this morning I spoke to this arrogant guy named sakhi telling me how there is nothing they can do coz they apparently debiting on the 1st