Prefix 9 added to my phone number in my city. Can't edit on Apple ID

A prefix 9 has been added after the city code to my cell phone number, resulting in a 9 instead of an 8 digit number. I can see no way to update it on the Manage your Apple ID page. Some other companies have an option for updating the number online, but not Apple. Anyway to contact Apple to find out how it's done? I'll need it for two step verification, as the old number is currently working, but will stop at some point.