You should have an experience in Phone verification using facebook, firebase or other things. Anyway don't care, however you can verify with Phone and receive accessToken as a result. Only Developer who has experience in this section, so that you can easily solve this problem. My budget is below $150.
8 freelancere byder i gennemsnit $136 på dette job
Greetings dear, I am professional mobile application developer having experience of more than 3 years. I am available for the job just inbox me so that we can discuss it further. Regards.