Warranty rights??!

Scrapy

I bought a blackberry in late December from carphone warehouse, recently had problems, returned the phone which they replaced with a new blackberry. It then had more problems within days or receiving it. I have been back to carphone and asked for the phone to be taken back and either swap for a different model (paying any extra needed) or have my money back as I am completely unhappy with the phones performance and problems it has caused. I am unaware of where I stand in this matter and what rights each party has.
Can anyone shed any light on how I can get this issue resolved?? Thank you

Tixy

You would probably be best to post this on a different board either - Consumer Rights
or Mobile Phones

But when reposting it would be useful if you could expand on when you went back to the shop, and what they said to you when you asked for a replacement or refund.