No that doersn't sound right, looks like it has doubled, so you need to contact eBay Customer Support from the Help & Contact tab above.
Be aware when you sell on eBay you do have two sets of fees to pay. The first you see deducted straight away when you receive that payment, is Paypal's fees, of 3.4% plus 20p per transaction, that is for their services in processing that payment for you. Then you receive eBay's invoice for 10% on all monies received, that is for using their worldwide platform to sell from.
If the figures still do not add up, then call eBay CS.
