i removed my SIM card and now my phone thinks it is lost or stolen! i put my same SIM card back in and it’s like it doesn’t recognise it?

my device was registered under my email address but was removed this evening and that account deleted from avast.com in an attempt to shut the siren and software off! i don’t know my PIN, i hadn’t set a recovery phone number and i can’t get the application to uninstall… AND I CAN’T USE MY PHONE! >:(

can anyone help me? would a full factory reset help?