same phone to multiple account

there is a problem with me on nopcommerce.
the problem is a customer has signed up two times with the same phone and different E_mails .
I need to make the phone number unique that can't be more than an account for one phone number.

You would need to customise the registration process
Or maybe there is a Plugin which can help
Dont know if this one is of use
https://www.nopcommerce.com/en/google-address-validator-by-nopstation