I don't think a physical SIM is a guarantee that the phone number remains intact. The SIM is a token in the system that links a piece of hardware to a phone number and that link is maintained by the carrier. My phone spontaneously stopped being able to make calls and receive SMS. I went through the usual steps to rectify it but no dice. The carrier had to manually reconnect my number because it had become a victim of their periodic cull of disused numbers. Took quite a few calls over a period days to achieve this. 'yes I have turned it off and on...' ad nauseum.