AUGUSTA – Verizon officials are warning business customers about a phone scam that’s cost at least one Maine company thousands of dollars.

The scam victimizes businesses with private exchanges that require users to dial 9-0 to get an outside line, said Peter Reilly, Verizon’s Maine spokesman.

Callers claim to be working on the phone lines, he said, and ask the person who answers to dial 9-0 to make sure the phone is working properly.