Contract terminated but still being charged

I had a month-to-month with Bodylab and then I decided to terminate the contract in 25 August 2017 now they sent me a notice saying my accounts has been handed to the lawyers as I failed to make payments and i owe them R 1 425. 00. When I request for a breakdown no one can provide me and they say all i should do is pay the amount.

They are such a ****!