I bought a Sonim rugged phone from Amazon not realizing it was locked with AT&T. I tried to get the code from the network, explaining to them that I don't even live in the USA, but they said they could not get the code. I also tried the manufacturer. I came across Cellunlocker.net and could tell they were legit. I got my code within two days, and my phone immediately linked up to my local network. Awesome.
Bottom Line: Yes, I would recommend this to a friend