Just wanted to know if anyone else has ahd the following problem and if so how have you resolved it..

I know a few people with vodafone (uk) storm's and up until the end of last week we were all messaging each other quite happily. Now my 8900 is saying that they are unavailable but upon speaking with them they say everytime I send them a message it says my details (cell number) are not recognised. They are available which is weird and I'm beginning to think maybe it's a vodafone issue as other bb friends of mine have other models and I have no problems communicating with them.