Signal Binding [4.0.0.0;5.0.0.0)

I am sorry, no good news. Now i got an Communication_error “NonSuccessfulResponseCodeException - [422] Bad response: 422”
How can i check that the phonenummer is or is not registered yet at signal. Maybe one of my several tests was succesful but not noticed be me. And if so, how can i remove my registration?
You wrote that now are two steps necessary. Frist try with SMS which fails and second try with vocal response. Do i need for the second step a new captcha link?

Thanks so far