A:Answer No. (A short, clear answer)
Longer answer: This phone is locked into using cell service, provided by GreatCall. You will need to transfer your number to their service and use their service.
The GreatCall cell service is OK (they lease bandwidth from ATT and/or T-Mobile, I believe), and their service prices are OK so long as you don't use too much mobile-data. But this phone is locked into the GreatCall service provider, and won't work with other cell providers like Boost, Mint, Verizon, ATT or T-Mobile.