Just call TSA or DHS and say "My friend Sheikh Mohammed bin Achmed al Jihad al Falafel was trying to take flying lessons as quickly as possible... and we would like to tell him that his order for 75 new cell phones and a spool of wire is ready for pickup. Can you call him at this number???"
They'll zero in on the phone in no time, and it will have nothing to do with cell towers. They may even provide some complimentary good samaritan aerial search coverage, thanks to some of our airborne "assets"
Kidding aside, I hope the aircraft and its occupants are all OK. Safe return to all.