Cancellation of gym contract

I was at Oakfield gyms for years. They sold the company to a Indian lady. I went there to cancel my contract completed the forms and she came out of the office and said she is the new owner and se will see to it. I didn't take a copy. Why I cancelled is because I was going to go for a neck operation and then I wont be able to go anymore. After 3 years now that the Gym Company has taken over they phone me and tell me that I must pay over 3000. Why only now do they phone and not phone me after a month or two to say there is no payment then I would have gone in to tell them and cancel it. They have black listed me for this and I feel they must be looked at