I want to transfer using my former phone number
Is your number active somewhere? (If the number is not active on any carrier the number most likely been return to the pool and can only be retrieved by the carrier that deactivated it)
I see you list the Moto G5 Play in your profile (and Previous Provider: Verizon Wireless) is this the North America Factory unlock version [XT1921-2] or the Verizon version (the Factory unlock is GSM only) .
to see if the number will transfer