Is it normal to have dual carrier enrollment?

My phone while attempting to re-enroll in my previous carrier crickets, advised me that I should close my account due to severe hacking. I did not even have my device unlisted for 30 days. My hackers took my phone number… Which should be at least 30 days. This happened with 2 phone numbers. I will delete one phone number find it enrolled as phone number two, while I’m with a new phone number as the primary? Is this something that is unknown or am I just in the dark input greatly appreciated.