Why are the saved numbers on my Nokia N79 appearing as new numbers when I receive...

[imported_Da_Vinci]

...calls and texts? As of late when I receive a text or phone call from a number already saved on my phone, it appears as a new number. For example, say I have a number saved as John, when I receive a text from John, his name does not show, but instead his number would. It appears like this, +447845934576. I was wondering how I can fix this, because it's very confusing when I get a text from someone and I haven't got a clue who it's from!!!

Thanks all!