Gym didn't cancel my membership & refusing to back-date refund

Aylesbury_Duck

Well that changes things. It sounds like you may have used the gym in the period in question. If their records say you did and you can't remember, I'm afraid you don't have grounds to retrieve the payments for the months in question.

It's best to be up-front about everything when you ask for advice, otherwise we are advising incorrectly based on only part of the story.