Gym Company - horrible service

I wanted to cancel my gym membership at Gym Company Randburg Square on 13 June and to date I have not received any response to my cancellation request. They claim to have called me on the 18th June but I have no record of this, my phone is always on

I also made follow up emails on the 25th, 26th and 28th June to no response. I went to the gym on the 18th July and I still couldn't be helped. Apparently only 1 person processes cancellations

I just want my gym membership cancelled ASAP