Not Honoring there contract terms

The Gym Company, clear don't know the meaning of a 12 month contract. I signed a contract with them on the 31 August 2018 which came to an end in September 2019. I went into the Branch (Bromhoff) where i had my membership to make the final payment for August/September 2019 and give 30 day notice of the cancellation. I January 2020 i received an email stating i owe money, however the contract was cancelled. I responded to their email informing their accounts department of the cancellation with a copy of my original signed contract. Today 12 March 2020, i get another email stating i must pay R1000,00 to have my name removed from ITC.