Vodacom shoving of old routers and "upgraded" but getting same speed.

I had just ended my wi-fi contract with Vodacom in December and upgraded from a 20Mbps line to 100Mbps line. They told me I'd get a new router with the new contract. They sent me a 4G router instead of a 5G router and I have seen no difference in my line speed. On top of that they added some 5Gig recurring data bundle to my uncapped wi-fi package. How does this make sense? My old router is faster and the one I still use. Now I have a 4G router I don't use and the same line speed. At an increased price.