Can't get them to cancel membership

I have made no less than 6 attempts by phone and by email to cancel my membership with Planet Fitness over the past 4 months but no avail. No one responds to emails sent to [Email Removed] and every call centre agent I have spoken to promises to action my request for cancellation and get back to me but no one ever gets back to me. This is simply ridiculously unresponsive customer service and I am at my wits end with what to do. I have now had to cancel the debit order with my bank to prevent them from ********ly and unacceptably taking more of my money. If anyone from Planet Fitness is still concerned about customers, then please pick this up and cancel the debit order at your end and please finally release me from an unhappy association with your company and brand.