The Better Business Bureau is warning consumers about companies that call or mail postcards seeking to extend a vehicle's factory warranty.

Several companies, including Missouri-based Dealer Services, are telling Utahns that their car's warranty is about to expire, even if their factory warranties expired years ago, the bureau said. Some residents have complained to the bureau that they cannot get the company to stop calling.

Dealer Services has an unsatisfactory record with the Better Business Bureau in St. Louis, due to unresolved complaints. The company also faces legal action by the Missouri Attorney General's Office, which alleges the company did not tell consumers it was not affiliated with auto manufacturers, was selling extended service contracts instead of warranties and violated the "Do Not Call" law.

The bureau cautions consumers contacted by a company that they are unfamiliar with to check the company at www.bbb.org.