Monthly double debit order

Joined Planet Fitness ( Just Gym) in Springs in 2017. A couple of months later after I've joined them, they stared double debit my bank account. A debit order would go through from my account, the following day I would get an sms from them saying "Dear member, we noticed that we have not received your latest payment". this sms is sent be cause the didn't find money for the second debit order. Some months when there's enough funds in my account a double order would would through and when it doesn't the bank charges me. if I go to the gym I would be denied access. and get told to get a statement from the bank. every time when I go to the gym I would have to carry a bank statement as proof that a debit went through. I've been sending them emails and calling the call center but no one was willing to help me until I send the last email to cancel my membership. A call center agents from their retention department called me, wanting to know why I don't wanna renew my member. I explained everything to him. He said he'll come back to me with a resolution. Its been 3 weeks now waiting for him to call me back