Membership Cancellation

Never join the gym cause it becomes a night mare when you cancelling contract... I joined the gym in February last year, during lock down money was debited from my account though the gym was closed. I cancelled my membership Mid April and I was told that I am not owing to my surprise the deducted money in my account last month and this month but I reversed it, only to get an email last week stating that my account is in areas... I called the head office today and I am told I paid for 11 months instead of 12, my argument is that I paid for 3months without using their facilities due to lockdown, how are they gonna reimburse my 3months coz am no longer around the area. Instead of him assistant my he threatened me with credit bureau.