Iphone 4 Black 16 gb - Blocked on UK network ?

For sale is a previously purchased iPhone4 16GB from Ebay but my seller was kind enough to have the IMEI blocked from the network I was on. I am not very technical so I have bought a new phone to replace this. The phone is fully operational, all email, safari, Skype, Facebook, facetime etc is working, all it needs is someone in the know to get the phone IMEI Unblocked. As noted this phone is fully functioning apart from it can not make phone calls and needs unblocking!! email me for more info please .... Ideal for a person who is going abroad..