Following the order by Federal Government that all telecom operators should block all sims not synced with the National Identification Number (NIN) within two weeks (from today December 16, 2020 and end by 30th of December 2020).
Here is how you can confirm your NIN is linked to your phone number ahead of the deadline:
Dial *346# and press 1 to retrieve your NIN. — (*The service costs N20 per dial.*)