phone wont let me contact mate all of a sudden!! help plz

[Aimsy]

Got a sony ericsson t630 and my best mate has got a K700i. i am on t-mobile pay and go he is on orange contract.
Been texting each other for six years using the same phone number - all of a sudden last week i go to ring him and for the whole week it says number not recognised please redial - but its the same number i hav been ringing for six years - i relied on the phone to keep in touch as they live to far away to ask what has happened - any ideas why all of a sudden i cant get in touch with my friend?? we spoke everyday i feel so gutted.................



thanks for reading - and suggestions?

[KidoBorg]

Well,

Try to restart your phone. If it does not work, try to contact your friend from a land-line or another cell phone.

Thanks,

Yeah ive tryed all that and the numbers still dead so i guess their numbers been disconnected or suspended damit