I am confused

Newbie

I am confused

I have had boost for well over 15yrs.  Now i have the plan that gives me 30GB of hotspot. I just received a txt that said that i was getting another 20GB of hotspot. now i went into my account and checked it and it says that i have 20 GB and the used shows that i have 30.  I mean 50GB would be great considering what is going on but my speeds slow when i hit 35GB of data. what is going on.  anyone please help me understand this.