Sony ericsson p1i wifi problem

I bought this phone from play.com just before christmas and have had a nightmare trying to get the wifi working. I'm using WPA with TKIP, and my router is in mixed mode. When I scan and click on connect, sometimes the phone says connection failed, but I can try it again and it suddenly connects. However when I try to access the web it comes up with "cannot locate remote server". When you go back to the wifi screen it's not connected anymore. I seem to have tried everything, turned off power saving, updated to latest firmware, done a master reset and spent a whole day looking through forum posts and still can't get it working. I've checked my router and the phone is getting an IP address. Quite frankly, I've had it with the phone and want to return it to play.com for a full refund. I think I'm within my rights to return it if it's faulty, but will play.com consider it suitable for a refund? I've tried to take stuff back to other places, and their idea of testing seems to be to switch on the device and go off to lunch and if it's still on an hour later then it's ok :rolleyes: Anyone know if I'll be able to get a refund? I'm really quite fed up now and I'd rather use the money to get a netbook or something.