hi i find many apps on google play that allow you to register only one account by phone ( i think it depend on MAC address filter)
how can register more than 1 time ?
afaik what prevents you from signing up again on a device is the device ID. You can change it if you are rooted so you can change the ID of your phone and it will allow you to be able to signup again. It's risky tho. Or you can try clearing the data and cache of the app and try to signup again, you can do this on some apps .