As bodda says, it *could* be a software glitch. When it has happened to me in the past, it has been to saving two or three numbers under the same contact name. I have to delete them, and add new contacts but only giving one contact one number.

Yes, you can do a factory re-set ( code is 12345) , you can also do what is known as 'hard re-set) #*7370# ( same code ) or you could also try installing ( or re-installing ) the latest FirmWare version for your phone

I have the E72, which I think is a great phone. THe Multi Scanner is brilliant.