Sale of Goods Act applies to any transaction done here. Imagine if it didn't. Every rogue in the world would open "head office" abroad and scam people left, right and centre.

If they wriggle and say you paid in the USA the Consumer Credit Act becomes your friend and you involve the CC company, provided the goods cost between £100 and £30,000 and you paid any part of that amount on the card.

Still think you need to give the supplier the chance to rectify the problem.