Rental is full of scratches, no response from Avis

I'm renting a car through Avis for 30 days. Picked it up last week and over the weekend the alarm started going off constantly. It kept doing this all week long so I took it back to Avis yesterday afternoon to get a new car. The staff at the branch first told me that there were no cars available, then eventually pointed out a Kia Picanto that needed to be filled up. Victor, the guy on the floor, told me to drive it to a petrol garage nearby to get filled up and inspected. I met him at the petrol station, where I noticed that the car was COVERED in scratches. I expressed my concern, but Victor said that they were just marks that would rub off. Even after I insisted, he didn't indicate any of these scratches on the form I had to sign, so I am highly concerned that I'll be stuck with a massive bill when I return this car.<br> <br> I've mailed and Facebooked Avis repeatedly about this issue, but they're not responding in any meaningful way.