Re: what is a contract?
Yeah, my thoughts were Contract Law, The Sale of Goods Act, and quite possibly Fraud.
HOOVER :
Some while back, 1980's maybe, didn't Hoover make an offer - buy one of our hoovers and get a free holiday ( transatlantic i seem to recall).
They reneged on it because they said it was too expensive, too many took them up on it and no-one could reasonably believe it was a genuine offer.
The Courts enforced it, certainly here in the UK, at a cost of some £148m to Hoover i believe. (Facts could be slightly amiss, happy to be corrected or properly informed).
Worst should happen is a full refund.