Hm I don’t think Wener’s answer was specific to your question.

So maybe you could have tried the command “2222 SET PROTECTION 1” (replace 2222 with your pin). BUT since Anti theft was disabled it means that if a new sim card was inserted in the phone you wouldn’t have been warned about it. Also according to what you say it looks like your current sim card has been disabled by your provider, so even if your sim is still in the phone it cannot work.

At this point you’re only option is to enable AT on the avast portal, which is less reliable since it needs internet connectivity. Have you tried that ?