Zonefitness and Nimble Collections

A few years ago I had a zone fitness account and paid it up in full according to the contract I signed with them how ever 3 months later they started deducting money from my account again without my concent .When I emailed them to refund my money as my account was paid in full and I never gave them any authorisation to deduct after my contract had been completed , they appologised and informed me that they are unable to refund me my money and offered me 6 weeks of free gym membership and will be closing my account permanently .Now 3 years later I am called by debt collecters stating that I owe them R232 without any explanation meanwhile I was unfairly treated in having my money basically ****** from me and not given back only for me to be handed over to debt collectors when I should be handing them over for not refunding me. The debt collectors Nimble group who have no regard for the Poppy act went to the extreme to even contact my family members about my account