Poor vodacome service

I have contacted vodacom multiple times about poor internet connection. When i took up my contract i looked at the vodacom signal 4g map and it showed I would get 4g. I do get 4g however it takes ages to download, i have tried multiple areas as well however its really slow. I had telkom before with no issues. When i run speed tests it shows 4mbps but i get a few kb per minute. I have reported it many timed done all trouble shooting but no help. I want to leave and go to telkom but stuck in this contract.