Overpaid a website via PayPal Subscriptions - Trying to deduct charges from my refund

Hi,

I cancelled a web hosting service a couple of years ago, and it wasn't unreasonable to expect billing oi also be cancelled. The service was paid via PayPal Subscriptions, I didn't realise I had to cancel this myself and small a payment (5 a month) have been continuing without me realising until recently.

When I spotted it, I contacted the company and cancelled the PayPal subscriptions, however, I'm having some difficulty getting the money back from them. They advise that because PayPal charges them transaction fees, they will refund me but first want to deduct these fees.

Where do I stand legally? Surely I am entitled to a refund as I've 'paid' for a service I haven't received and I don't think I should have to incur the fees/admin costs as part of a refund?

Thanks

Abe