Ebuyer are wrong to point you in the direction of Epson with regards to problems/customer service for this device. As a new product sold directly to you, the contract sale lies between Ebuyer and yourself.
If there is an issue with the product detailed for the German market I am not so sure. Most European products are manufactured to be able to be sold to many European countries, it makes no sense in planning or monetary terms to manufacture a product soley for sale in 1 country, unless there were specific legislative requirements for that country.
You don't mention what makes the product unfit for the UK market, and if you have the steps of started RMA procedures with Ebuyer without checking if you possibly may just need to change a menu setting or suchlike then I can probably understand the flippant response from Ebuyer.