MTN Worse Service after 10years!

I am highly Dissapointed and am busy taking this matter Further. Been a LOYAL MTN customer for over 15 years. Late in July I requested to be moved to Prepaid. Ever since the 11th Aug 2026 I am unable to receive Incoming calls. The settings on my Huawaei says incoming calls barred, if i want to deselect it, it says enter 4 digit code that NO ONE to date has given , how can i receive NO incoming calls when i have a sick father at home and if theres an emergency for my son at school or home how would ANyone get hold of ME? worse part is NOt the store or staff could assist the one agent told me she doenst know her CEO mtn is such a BIG company she doesnt know her CEO WOW! Resolve this becauase hw can i go through this something that is Not even my fault!!!!!!!!!!!11