We recently released a game and it was made on Unity and it supports client and web. So in the past we already had people hacking the game by changing statistics and virtual currency. These issues got fixed through cloud script.
Now we got a new issue. Some people are mass creating alt accounts. Yesterday I was working on the project and noticed around 500 account being made in the last few minutes. They all used some fake email for example "fun1234", "fun3214" and etc. After that I just turned off the API features for the project so we can possibly fix this.
Also today I noticed that more than 30M API calls were called for ServiceHealth status.
I had some ideas in mind to prevent players from creating a lot of accounts simply by setting account username to the device id the user is using. And to let user register multiple accounts I can add one number to the end. And so if there are more than 3 accounts created with the same ID it won't let the user create a new one.
So my question is that: are there any ways to limit user account creation and is there a possible way to keep track of users calling the APIs so they can be automatically banned?
Here are the pictures that I have. One is from the PlayFab dashboard which was taken by me of the API calls and another one shows the console of user creating the accounts.