Rental Company in the US is Dishonest, Overcharges

They did not provide the reserved vehicle and took advantage of our lack of English skills to overcharge us. Even though we refueled the car and confirmed it with the inspection agent, we were still charged an extra $20 for supposedly not refueling it. After complaining to the manager, the receipt was corrected. The manager said we would be refunded, but since it was a credit card authorization, we have to wait for the billing cycle to know if we were really refunded.