Unhappy client

My cell phone is disconnected from receiving calls .i have called a multiple times no one is able to assist me. I have 3 contracts with Mtn i was due for an upgrade on the 23rd of April 2024 than i opted for a data contact from the my clients cant call me. I am an accountant i dont have a job i really on my clients to call me but nw am frustrated its been 6 days can someone please help me