GM direct-mail, phone tactics upset dealers.

General Motors' direct-mail campaigns are undermining dealers' efforts to make customers loyal to their own GM dealerships, some dealers say. The campaigns have caused dealers to become more suspicious of the way GM fields consumer inquiries from the Internet and toll-free phone lines. As GM requires more detailed sales reports from dealers, some dealers worry the company is using the information to promote rival dealers. Dealership employees who have bought or leased vehicles from the stores where they work have received letters from GM promoting competing GM brands and offering the address and phone number of rival GM dealerships. ``A salesman who has worked for me for over …