my friend ran away at 16 her mom was the same as you she kept on texting but got nowhere. she then found out where she was but didnt let her daughter know. she sent the odd message just saying hope your ok and my friend soon went running back home when she realised life is tough,
maybe you have to let her make her own mistakes, putting the pressure on might make the situation worse
i moved in with a mate at 18, expecting it all too be good but i was soon begging for my room back after 4 weeks