My number has been temporarily blocked why please

I have done the sim update and linking of NIN to the sim for long but got surprised when i was told to link my NIN and update...

Sim blocked

My SIM card keep saying you are temporarily blocked contact customer care

I can't check my balance or even use the data I just got because my mtn line keeps sending me the same massage that my line has been temporarily blocked, please I need a way to...