I met this problem when I activated my gig and I solved it luckily. I did this:
(1)If you use a PC and you better use Chrome or Edge.
(2)When you publish your gig, and failed to verify, and receive a note like this: Something wrong with your phone number, please check and try again. You can do this:
Click Ctrl+Shift+I,or open your Developer tools of your browser.
Click Refresh button, and use 【Empty cache and hard reload】.
OR clean your cookies and cache, use Ctrl+Shift+R to do the same.
Did all this above, I made it.