I upgraded my daughter's phone last month. She get a 'network unavailable' message. I have tried manually connecting, and have tested the SIM in another phone - it worked. The coverage here is very good and the problem persists at home and away. Another sim in her phone didn't work either so I assume from all this that it's a handset problem. Do you have any ideas of anything else we could try or shall we return the phone for a replacement?