unhappy

I have currently got a Cell C contract with a home rooter, about 3 weeks ago i received a call from Cell C saying that i am due for a upgrade. my response was what they have to offer and they told me that got the same package I'm currently on for R200 where I'm currently paying R400. I agreed to do the upgrade and was told my new rooter will be sent to me. last week Monday 28/05/18 i received the rooter and when i opened it it was a mobile rooter so i called Cell C to say that i currently have a home rooter and they didn't send this to me they then asked to send it mobile rooter back and when they receive it they will send the home rooter. i sent it back on Thursday i then called them again yesterday 04/06/18 to follow up with them only to be told that i cant get a home rooter for R200 i then said that i was told i can upgrade for that price and want it for that price. the woman on the phone said no i cant, my question is why does Cell C tell me one thing then change there mind. If i don't get answers from Cell C soonest i will be escalating this matter further