no change without my consent

Telkom just changed my prepaid no to a different no without my knowledge or consent. am expecting very important calls on the no they deactivated and am told by the call center that I have to wait for 72 working hours for my query to be resolved? this is so unacceptable and I cannot wait for that long for my no to be reinstated, this is costing me job interviews am waiting on and putting my life on hold.