WORST SERVICE - MTN

I’ve been trying to sort out MTN number with MTN since last year but no luck! I spend hours calling 135, no help there! Each time they transfer me & the call gets cut!!!!!!! The last I managed to get through, I was told that they cannot find my number or details on the system yet I’ve had a contract with them for YEARS! It’s despicable how they treat their customers esp those who have been with them for DECADES! CAN SOMEONE HELP ME PLEASE!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!