Mtn uncapped router

So when you take a router for R295 pm and it says uncapped and will slow a bit after 300gb does it mean your usage should be limited, I've not even had this ****** thing a month and it's given me no wifi or signal anymore, I call mtn and they condescendingly say, ma'am uncapped does not mean unlimited, it's only 130gb pm, not according to my contract. then what the hell did I take this thing for,

It is not worth it, I just want to cancel this thing

Props to them for answering the phone after 8pm