Avis Car Rental

DO NOT RENT FROM HERE. We rented through Costco Travel. Our price was for 244$. On the day of our rental, we called them to see if we can change the pick up times and pick it up earlier. Mohamed said "yea, I take care of you." Apparently, that meant he was going to charge us for five days instead of four and on top of that he couldn't even explain to us why we were charged more. So our bill ended up being 367$. Turns out we were charged 60$ more for the day and 49.75$ for insurance. We never authorized the insurance charge and did not get the chance to decline them. When we called someone on 5/5 Friday to dispute these charges, the guy said to go see an Avis to remove the charges. Since we were out in the middle of nowhere, we couldn't go find one so the guy on the phone said to go on Monday when we returned the car we will need to get Mohamed to reverse it. Well Mohamed refused to reverse it. He said we got the manager's special so we needed the insurance otherwise our bill would've been another 45$ more. We called Avis customer service and they said they couldn't do anything because we authorized it. However, we did not and were not informed. Mohamed just said to initial stuff. Basically we are out of luck. We will be sending a formal complaint to Avis and Costco Travel for the ridiculousness of this scenario. I want Costco to be aware of Avis.