How do I remove this number and where does it come from?

[Kimmieee89]

Whenever I have the option to sign up with a phone number, it suggests two numbers and one of them is totally unknown to me. I do not recognize the number at all. The phone is bought second hand and I did a factory reset to it. It is a Oneplus 5. How do I see where its stored and how do I remove it? Have I been hacked?

 

[me just saying]

do you have any third party messenger apps that provides free phone numbers, google voice or similar services?

 

[B. Diddy]

Welcome to Android Central! Sign up for what? For new accounts in various apps?

 

[mustang7757]

[Moved to 1+5 forum for specific traffic]