You do NOT need a receipt to take goods back.
If you say when and how you paid for this and who served you they should be able to trace.
Go back and if they don`t tell them that you are informing the local Trading Standards Officer as they are breaking the Law (find them in your council) and then inform them that you will take the barstewards to the small claims court.
And then you are supposed to tell him what a complete wanker he has been.
Follow through your threats but I bet you get a response.
