I signed up for the gym a couple of months ago when I was 17 (I still am). I did it on-line and the gym asked for my D.O.B which I gave. Last month I didn't have enough money in my bank at the time and a debt collection company then charged me the original fee plus the admin fee which I then paid straight away.
I emailed them a couple of days later to ask for the admin fee (£20) back as I was under 18 and no debt could be taken from me. They asked me for proof of age which I provided and they then said that they are cancelling the contract as I am under 18 and I will not get any money back.
For a start can the debit collection company cancel the contract themselves and can I get the money back as I am under 18 and they knew my age from the start.
They need to improve their systems to pick the issue up.
I can see why they won't refund your payments since you have been able to use the gym facility. I can also see that they would argue that the debt collection firms fee is your problem.