Consumer Alert: Beware of "unspecified" bills from car rental companies

If you don't pay, you'll end up on the infamous Do Not Rent list

Car rental companies are sending their customers bills without even bothering to tell them what they're for.

It happened to Donna Sundstrom when she recently returned her car to Avis at Seattle-Tacoma International Airport.

Although Sundstrom insisted on doing an inspection with an Avis employee, she received a $1,023 bill for what she called "unspecified…