under consumer rights i am entitled to my money back
Possibly, it will depend upon the circumstances. You can find information on your statutory consumer rights online, or consult Citizens Advice.
Unfortunately, having rights is one thing, being able to enforce them against distant, un-cooperative eBay sellers is another. The reality is that the uncertainty and possible cost of legal action seldom makes this worthwhile for most items bought on eBay.
You also have to remember that the user agreement even warns buyers that "eBay does not guarantee the existence, quality, safety or legality of items advertised, or the truth or accuracy of descriptions".
Buying from unknown sellers on eBay isn't like buying from the shops. You can't say that eBay didn't warn you about the risks of buying here. It was your own choice to accept them.
