Unreliable Vodacom network connection

I have 2 data sim contracts with Vodacom and have experienced issues with connectivity for the past 6 months. I have told them that my sister uses one in Pietermaritzburg and I use the other in Richards bay, give them her number and they have failed to call her on 3 occasions. I was told due to the historical issues, that I could cancel for free but was given the run around for 1 hour to no end. I am so fed up with Vodacom and they wish to go to 5G when they cant even maintain their current network commitments.