Minutes not rolling over

When I took out my contract I was told by the salesman that my extra minutes and data would roll over to the next month. It has been a year and five months and this matter is still not resolved after countless visits to stores and getting the run around from Vodacom. Today I speak to someone in the call centre and they say that on sim only contracts, minutes and data do not roll over. However my husband has a sim only contract and his do. That is one of the reasons he suggested that I take that deal. Now they are saying that only on "open contracts" do they allow minutes and data to roll over. My husband has just upgraded his contract and I heard the sales consultant say that his minutes will roll over for 30 days. So what is the actual truth? Don't recommend Vodacom. The after sales service is shocking and it really seems like the staff have no idea what is going on and they are selling you features on contracts that apparently "don't exist" for some and yet does for others?