What happen if someone do not accept the GDPR alert inside asp.net mvc core 3.1

I am working on an Asp.net MVC core 3.1 registration web site for the US market, where the users enter his/her mobile number >> and on the next screen they enter their info to register with us. and we want to track the users who enter their mobile numberx but do not register.and since we are tracking the users' actions, so i added the GDPR alert by following the steps mentioned on this link @ https://docs.microsoft.com/en-us/aspnet/core/security/gdpr?view=aspnetcore-3.1.

but i am not sure what i need to do then?. I have these 3 questions:-

Question1) If someone accept the alert, then this mean that we can track if he did not complete the registration?

Question2) How i can know that the user accept or did not accept the GDPR alert inside my code?

Question3) If the user did not accept the GDPR alert, then is it still fine to track if the user enter his/her mobile number but did not register?