Sending back broken Sony Ericsson phone

Currently, I had bought a M600i from craigslist. He told me that the phone part doesnt work but the other functions are good. I tried that Vodaphone mod and switching it to automatic connection, but no help. I searched online for a long time but cant find anything.

If I go to a phone shop, itll cost average $60 to fix it. Should I do this or ask the guy to give me his reciept so I can send it back to SE? Or does anyone know how I can get the phone working again?

ps. the phone is absolutely 10/10 condition and I dont think he dropped it or anything..

When I put my SIM card in, I can log on to the main screen and use the functions but it never finds a provider.. always says searching..

I hate to say it but i think that you have give it to a shop.Sorry!!

So before I give in $60 of my hard earned money that easily to the shop, you dont think there are any settings I can change in order to make it work? I dont want to give it in so they fix it in 3 mins and charge $60.. if you know what I mean.

I'd ask him for the receipt - sounds to me like the phone could be blacklisted (i.e. stolen and forebidden from use by the networks...) I hope I'm wrong but it is a possibility...

you should take the phone apart (ignore this if its never been taken apart) and check to see if the signal chip is getting a connection to the mobo.

i'm not sure but i'd try
the master reset