BuddyPress.org

Hello there,
I wanted to make my users able to register through their phone number without having to type their email too, after long thinking I had this idea.
I changed the email input type to text and tested if the typed in text is an email so the user is registering through email, else if it is phone number then add @mail.com to it, I also got the activation key from datbase and sent it to users by sms.
my problem is that the sent activation key is too long to be typed, I tried to alter the activation key in database when user is registering but when the user enters the updated activation key, the activation page is just refreshed and the code field is emptied.
any ideas? I want to make the activation key just 6 characters long