From time to time I'm asked what to do if a new product is faulty. Unless there's a simple 'fix' to try out (eg dirty jack sockets, amp reset) I will point them back to the store where they purchased their gear to resolve the problem, and in most cases stores are very helpful.
But should anyone have a problem with a store/supplier in the UK, I came across the following nicely laid out factsheet from the DBIS in the UK, which is well worth a read and helps to clarify consumer rights.
A key point of note, contrary to popular myth, is:
It is the seller, not the manufacturer, who is responsible if goods do not conform to contract.
http://www.berr.gov.uk/whatwedo/consume ... erentfault
Hope this is helpful.