Budget Car and Truck Rental

I reserved a car and I made a slight change to my reservation when I went to picked up my rental, and they ended up charging me a premium rate. When I made my reservation they quoted me various prices for 1 or 2 or 3 days etc. I was ok with any of the rates they quoted over the phone. I told the customer service person my situation; yet they did not mention if I added a day or subtracted a day I would be charged a whole different rate. I had to make a drive out of town because my mother-​in-​law was hospitalized; so it was hard for me to determine exactly how long I would need the rental for. Since I had already reserved it the rates should of remained as what they had quoted me over the phone, but that was not the case.
I was not happy.
And generally I found the staff unfriendly and unhelpful at this location in particular.