Debit Oder Dispute and cancel from Planet Fitness Gym Rustenburg

Good day, i am very disappointed o Planet Fitness, They are debiting into my account and I do not have contract with them. From my FNB Account, I tried to stop and cancel debit order however they try to access debit order with different company description daily and that is cost effective for me. Declined debit order charges me. I would like them to refund me and stop debiting from my account. I tried to contact them with no luck and they debit different money daily and if it was an instructed and approved debit order It could have had a debit order dates.