It's hard to advise you with so little information.
You don't have an eBay shop, which would be the only service for which eBay charges a subscription.
You don't appear to have sold anything for a long time, but if you still owe eBay any fees it will keep on appearing. To check, get an itemised breakdown of your invoice here: http://pages.ebay.co.uk/help/sell/invoice-display.html.
If this isn't the reason, are you sure it's eBay that is charging you a subscription? There are some risky pop-up ads here that pretend to be a competition, but then take regular payments from your credit or debit card. These have nothing to do with eBay. If you can't find how to unsubscribe you would need to contact your card issuer.
