How to reset my mtn sim card

How can I unblock my MTN Sim card without visiting mtn office phone number is 08104831973

I am in qatar presently , ,my simcard prompt sim error. 1. please i will need a new sim card or esim 2. i need to keep my mtn sim card number

I need to block my lost sim card

SIM Not Registered! My sim says not Registered. I have tried all cheat options, turned off and on the phone, removed and reinserted properly, reset the network on the phone but...