Device unlock problem

I obtained a phone from a friend that he was no longer using, to give to a medical student I'm supporting.  Not able to unlock it on the network as get "Oops! Looks like we're having network difficulties. Try again later." error message repeatedly.  I see on the forum that many others have this problem.  Have tried using the contact info of the owner, and it says the phone number doesn't match the IMEI, and of course it doesn't , as he has another newer phone active on that line.  What to do now?