Stolen IMEI Activated at Verizon

A  person, whom I have no idea is, opened a Verizon account using my stolen phone IMEI #. Verizon placed a block on my AT&T phone which caused AT&T, to suspend my service. My phone has been active with AT&T for years. Whoever stole my IMEI # seems to have skipped out on his Verizon account with a balance owed.

Even though the phone was purchased by me and activated with AT&T years ago, Verizon is holding my phone hostage because of some stranger's debt. I need Verizon to release my phone IMEI so AT&T, whom I have the account with, and who has my phone registered with them, can make my service active. I have spoken with AT&T as well as the Verizon Fraud Dept, Collections Dept, Service Dept, and Finance. Everyone just points fingers and refuses to take action. 

I need Verizon to release my phone IMEI so AT&T, whom I have the account with, and who has my phone registered with them, can make my service active. I need an investigation opened at AT&T to pursue getting my phone IMEI released, but can't find out how to.