plasma tv stopped working after 3 weeks

You can insist that they suply a replacement or a full refund
as the tv is only 3 weeks old.

They can however state that they will get it repaired
depending on what the problem is.
If it's a major fault then they might be better of replacing the tv
but it might be something as simple as a fuse that has blown.

If they don't want to know and try to fob you off then I sugest
that you write a letter to the shop in question outlining that
you will give them (say) 14 days to sort the problem and if they fail
that that you will contact your credit card company requesting a
chargeback in which case you will also give them a copy of your
letter and any responce of the shop in question.

WHEN you do send a letter make sure that you send it recorded
and make sure you keep the receipt from the post office as this
will be your proof of postage and has a tracking number.

As this tv was a brand new you would at a minimum have 12 months
manufactory warranty.

Best of luck and let us know how it plays out.


Gerrit

You do not have to put up with a repair. The sale of goods act allows u to reject faulty goods and demand a full refund or replacement within the first month.