Budget Truck Rental Gave a set price, had us pay, and then the credit card was charged more later when told we didn't owe anything else Internet

We were making a very big move, on limited income, from Michigan to New Hampshire. Budget Truck was slightly less than U-Haul, so we went with this company. We were given a price of $749.00 and $82.00 for the car dolly. 

Upon arriving at the rental shop, no car dolly was available. The employee tried hard to locate one for us at another location. No luck. I appreciated that she tried to help but in another sense...shouldn't they have checked their inventory before hand? We reserved the truck over a month ago and now we were going to have to drive our car, with more tolls and gas, than we expected.

She took off the car dolly price and then we added insurance ($27.99) for the four-day trip. We also had purchased an additional day since the apartment would not be ready until the 5th day.  She told us that if we could not get the truck back by 5 p.m. on the fifth day, we should call and add another day to our rental...this was fine. 

Upon arriving in New Hampshire, the apartment complex told us they still wouldn't have the apartment ready until 2 days later. I called Budget Truck and added 3 additional days, we paid with our credit card. I told them we did not want insurance because the truck would be sitting in my father-in-laws warehouse. The employee charged us $60.00 each day and instructed us that when we arrive at the rental location we will have to pay the $.75 a mile extra. That was fine. (Now that i think of it, how do they know how many miles we had used since arriving in New Hampshire? Do they use Mapquest? We had unlimited miles for the trip.) 

We moved into the apartment, was finished by 11am the day the truck was due. We paid the rental attendant the additional miles and were on our way. 

Then four days later, we have a large amount taken off of our credit card, over $475! I called Budget Truck and she said we didn't pay for the additional days and they were $75 a day, $27.99 a day insurance, $30 in refueling (which it was full), and $62.76 for miles. I told her we have credit card proof we paid for the additional days and we paid $60 a day and paid for the miles the day we arrived. We even filled out the fueling coupon, that was inspected, when at the drop-off. She said we would need to send in the paperwork.

After two weeks, I called the company again. They apologized for the "inconvenience" but they still had to charge the additional $15 a day we didn't pay for (because I guess it is $75 a day and not $60) and we had to pay for the insurance. She did refund (after about 7-10 days) our over charge for the gas fees. I was really devastated. How could the phone agents not know what to charge people? If I called the company it was because I was making sure we had everything covered. That little four-hundred something charge ruined us paying rent on time and I am glad we have electronic banking and proof that we filled the d**n truck up.