I have a similar problem but I am still in the application process to become a freelancer on upwork.com so I can't get past the telephone verification step. I have checked my cell phone number and had the site send me a text multiple times but nothing has come through to my phone.
Hello! I am having the same issue as some of the others. Still stuck in the application process because I entered in the wrong phone number in the beginning and cannot change it. The number to verify is incorrect and I cannot change it or the country code, it will not allow me to. It is impossible to speak to someone about this. How can I go back to change my phone number?
Based on the address you add on your account, the area code automatically populates on the mobile number field. Are you using a different mobile number for your account?