The other day my phone said it was receiving no network occasionally it would go up half a bar and say emergency calls only, i went to the 02 shop as soon as i walked in the shop i got a full bar of signal as soon as i walked out got no signal again!! Walked round to the other 02 shop and it did exactly the same! Tried my sim card in another phone and it works fine, its a Sony Ericsson k800i, anyone else had the same problem or kno what could be wrong?