Had nothing but troubles yesturday getting it to work even after removing Rogers One Number, but the toggle suddenly worked this morning. Might have taken some time for the RON to turn off completely.
Mine actually offered me the choice before I could even ask. I think they were so busy that they were more than happy to let me take the iPhones home to do the sim switch.
@IxhunterI ordered mine through Amazon.ca and got a USPS number that's tracking the package through LA currently. Sometimes the tracking numbers take a bit to show up.
It's part of their value packs, it's called Premium Voicemail-To-Text now, make sure you tell them it's for an iPhone though so they provision it correctly.