Planet Fitness is *****ing my money

Since last year I've tried to get rid of this gym. I finally paid off my contract 2 months ago (R580.00), and yet they still double bill me every month. I think this month is probably the fourth time they've taken 2 debit orders from my account. They refuse to acknowledge that I'm no longer a member. I've emailed, phoned, gone in to speak to managers, but nobody responds. The manager is never even at the branch.