Incorrect debit and no response from \help"centre"""

I have long since ceased being a Planet Fitness subscriber and had paid for my membership upfront, rather than by monthly debit. Yet in January I was debited over R400 from the gym with no explanation. I called the service centre but was directed to email them at [Email Removed] with my query and would receive a response within 72 hours. I did this and as I write, over three weeks later, have received nothing. With no explanation nor effort from Planet Fitness to follow up this constitutes theft. I am not sure how they even still have my bank details on record, or according to what stipulation they felt it justified to debit me an arbitrary amount for services I do not receive.