Gym membership cancellatin

sueylouy

I cancelled my gym membership in writing back in March and received a writen confirmation back from them, which unfortunately, I didn't keep. I expected them to take April's subscription but was surprised to see that they took May's payment also. When I rang them they told me that the confirmation letter stated that I needed to cancel the payments to them with my bank, which I failed to do. I didn't realise I had to do that as I wrongly assumed my cancellation letter to them would suffice.
They are refusing to refund May's payment and I'm hoping someone can tell me please if this is legal. Many thanks.