Great customer service upfront but terrible communication at the end

Renting a car from First Car was the simplest thing - no hassles. Getting the car from First was a piece of cake. The lady at front desk was helpful and patient. Explained things to us clearly and helped us get a reduction in the amount blocked on my card. The car was in excellent working order and was a charm to drive. Everything spiraled when we returned the car. On our way back into town we checked in with the call centre whether we could return the car a day early and at a branch closer to home which they said would be fine and we'd get refunded for the early return. We rushed and got the branch an hour before they were scheduled to close. Unfortunately when I got to the branch it had closed early without notice. Their after hours policy was to drop the key in the window and leave a blue form inside the car. I did not have a blue form. After checking in with the call centre and not getting much help, I called the branch's after hours number and was told to leave my copy of the checklist (yellow form) in the car, take a picture of it and be on my way. I did this begrudgingly because if we were to be blamed for damage to the car, my original form would be with the company. A few days later I heard back from First Car with the invoice which had various extra charges that were not well explained. I queried these via their online portal. It took a momentous 2 weeks to finally clarify all the extra charges. The person in charge of my query only answered one of my questions at a time and immediately closed the query once she'd responded. Each time I had to reopen the case and, again, list my questions. Each time she only responded to one question and the process continued for 2 weeks. Initially she did not even read my questions and just resent my invoice with no clarification. This customer service has left a terrible taste in my mouth and I will not be renting from this company again. It was sunshine and happiness in the beginning when they wanted my money but it quickly turned sour when it was their turn to refund my money. I was patient throughout and did my best to be clear and succinct in my query but my patience wore out in the end.