[uxp]

Not all numbers are portable in all cases. When my fiance and I decided to both move cell carriers onto a third carrier to get a family plan, only one of us was allowed to transfer. No way around it.

Also, it's still basically impossible to transfer a land-line number to a cell number, as they are apples and oranges.

[18pfsmt]

This is simply untrue as I've operated. These companies will often take advantage of you if you are not aware. If you utilize a competent SIP trunk provider, they will go to bat for you, and you should never relinquish a number. I realize ILECs present an issue, but again, the law is on your side. Document everything. I will help you for free with this, no problem. Not sure what there is to do post-facto, but I'd raise holy hell.