Quality in Microsoft Azure system application

I have a challenge with my application on Azure. Created two keys to act as the primary key but there's a problem in my cloud Azure. created application system and made unique identifiers for the system as the phone number and ID number but some of the users seem to share phone numbers and most users don't use ID numbers or share ID numbers too. 
How would you go about solving this issue to enable the system to recognize the number of callers within the system even when they share phone numbers and also repeat callers and most don't have ID numbers users and produce an accurate number of users within the system when the records are recorded by the end of the month. Please help me out.