Hi, I am in the process of creating my signup system for my app. Users must complete the following sign up form: Name Username Email Password Mobile Number Once a they complete the form a 5 digit pin SMS is sent to the user. They must enter that 5 digit pin to confirm their mobile number. Users will have 1 of 3 statuses: Pending - user has completed the signup form, but has not confirmed their mobile number with the 5 digit pin Live - user has completed the signup form, and confirmed their mobile number (and are now able to use the app) Banned - user was live, but was banned from the app for posting inappropriate content SIGNING UP When a new user signs up, the form checks to see if the new mobile number is already associated with another account, and if it is, what status that account has. - if the account status is 'pending', then allow user to proceed and send the 5 digit pin - if the account status is 'banned', stop the user and notify them that they must use another mobile number QUESTION - if the user enters a mobile number that is already associated with a 'live' account, what should i allow the user to do? At first i was thinking of notifying them that, that mobile number is already in use, however, what if the user had lost their phone and is purely trying to sign up again on their new phone (which has the same mobile number)? Any advice greatly appreciated, thank you.