Hey guys.. so I purchased a samsung galaxy s vibrant off somebody through kijiji, he said the phone is supossed to be unlocked, when I go into the network settings, I can choose between rogers, telus and bell, I choose telus, it says I'm with Telus. However when I can't make calls or send text messages, but people can call me, on top of this, when I turn on the phone it says enter unlock pin code, what is this code, how do I fix it?