I have another related problem: my phone was pre-owned and it shows the previous owners number in the Mobile field. I've done a factory reset but it didn't make a difference, the other number is still there.
Already looked at that but no can do... only the Name and Last name fields are editable, the mobile field is greyed-out... I can add another field but the original Mobile still remains, like it's a default the same as E-mail and Ovi.
It is very simple. Even if you don't have balance in mobile account. CAll to Customer care and provide the details they will tell you your mobile number....