PRO activation and credits are assigned to your OBDeleven account and are there until you use it to one-click apps or delete your account. The credits and/or PRO license cannot disappear on the account until it has ran out or has been used.

In most situations the user has forgotten which account he was using before and created a new account. That also applies whenever user has logged in with Facebook, Twitter or Apple ID before linking it with the email account or vice versa.