Gym nightmares

Cancelled my membership with more than a months notice. Phoned in to confirm cancellation and I was advised if I did the request online it's done and no need to worry. After the year fees was still being deducted from my account and I eventually stopped the debit order. Now I'm getting threats via email on outstanding monies. Not my fault your online cancellation system does not work. Even received a mail confirmation cancellation has been done. So next step Ombudsman and Consumer Commission.