Samsung Finesse Metro PCS help! I can't get it unlocked, that's how I purchased

[dx7alex]

it! Locked!? I bought a used phone from a guy. The battery was almost dead when he gave it to me so I put it to charge and after it charged a bit I started to play with it and I noticed it asked me for a unlock code. I texted him and he said "thats why its cheap, ($40) because i dont have the code" so i am thinking it might of been a stolen phone, you would imagine he would unlock it before selling it, at least he would know the code. So I went to a metro pcs corporate store, the guy temporarily unlocked it, he dialed a certain number using the DIALER, he told me, but he told me fast! He said once the phone turned off, it would relock again! and it did! Does anyone know how to UNLOCK it? I have tried the last 4 of the guy who sold it to me, 0000 1234 2222 3333 all the way thru 9999, and nothing! Please help!