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If goods are not of satisfactory quality the buyer is entitled, if he acts within a reasonable time, to reject the goods and get his money back.
Reasonable time is not defined, but it isn't set at thirty days.
The relevant Act is:-
Sale of Goods Act 1979. Supply of Goods and Services Act 1982. The Sale and Supply of Goods to Consumers Regulations (following 31/3/03 transposition of Directive 1999/44/EC).
See here for information on your rights
Your local Trading Standards are always worth a 'phone call. Some will take up the cudgels on your behalf.