I can’t use Privacy.com because they use cellphone numbers. Supposedly, someone had used my number previously to sign up and now I cannot make an account since

I can’t use Privacy.com because they use cellphone numbers. Supposedly, someone had used my number previously to sign up and now I cannot make an account since that number is “tied to an account”. It’s why I hate this standard of 2FA/“identity verification” with something as antiquated as phone numbers. I’d love to use their service, but as of right now I’m simply not allowed.