samsung galaxy s2 brand new swap for blackberry 9900!! !

samsung galaxy s2 brand new, iv had the phone for aprox 3 weeks, i have the invoice to prove! it has only been out the box while i tried it out but i prefer blackberrys.(phones with buttons) phone is on vodafone but i tried an O2 sim in and it accepted it,dont know if its open to the other networks. want to swap for blackberry bold 9900, must be around the same condition as my samsung, or sell for 250 text or ring on 07917 823 505