Worst Health Business Company

During the lockdown period in 2020 Gym Company had been deducting double every month. I had tried to call them but there was no answer. When the places opened again I physically went the Gym Company to sort out my account but they did nothing. I went to their accounts people with all my statements and was promised an email with the outcome. Still I did not receive an email or any kind of communication. Now I receive an email telling me that if I do not pay R100 and sign up with them, they are going to blacklist me for arrears. Can someone please tell me what to do to put an end to all this... They are supposed to be a health Company but they put more stress on people. Not sure why they are still allowed to continue to do this to people.