1) Send the item back and report to Trading Standards, or the C.A.B. first is the process now I beleive.

2) Send it back demand a refund quoting your statutory consumer rights and threaten to sue if they ignore you. Of course all this depends on the value of the item - is it worth it - and assumes it was bought within the UK. Sellers in the UK are not exempt from UK regs because they operate through Ebay.