My bank shows two payments and order numbers that I do not recognise.
Saying that "you don't recognise" these orders sounds a bit vague. It isn't even clear whether you mean purchases, or selling fees.
Before trying to contact eBay, if you haven't done so already try checking your own account records. You will find your recent purchase history in your "My eBay" pages. Is there anything there that you didn't buy? Could a member of your household have used your account without permission - it happens!
If it's selling fees, you can get an itemised breakdown of your invoice here: http://pages.ebay.co.uk/help/sell/invoice-display.html.
We don't know whether your bank account shows payments to eBay direct, or through PayPal. If through PayPal log in and check your recent transactions history for any unrecognised payments.
If this doesn't solve your problem and you suspect that your account has been hacked, see: https://www.ebay.co.uk/help/account/protecting-account/get-help-hacked-account?id=4196&st=12&pos=1&q...
