Telemarketers not only have to honor the national Do Not Call List, but avoid calling consumers on the individual state lists as well. In Missouri, Attorney General Chris Koster has sued a California telemarketing company he says ignored the state list.

Koster filed suit against Credexx Corporation, d/b/a Auto One Warranty Specialists, based in Irvine, California. Koster said telemarketing calls were made to consumers in an attempt to sell products described as automobile warranties. A number of consumers complained to Koster's office that they had registered with Missouri's Do Not Call List.

"Missourians who register with our No-Call list do so with the reasonable expectation that unsolicited, harassing calls will be substantially reduced," Koster said. "This office is committed to vigorously pursuing every telemarketer who violate our No-Call laws."

Koster said he is asking the court to stop Auto One Warranty Specialists from making calls to Missourians on the No-Call list who have no established business relationship with the companies. He said he is seeking the maximum civil penalties for each violation of the law, in addition to the costs of the investigation and prosecution and all court costs.

Koster said he is cracking down on businesses that market auto service contracts and auto additives as warranties. In November, he filed suit against six businesses for tactics he says they were using to try to trick people into purchasing bogus auto warranty products of limited value.

Earlier this year The Better Business Bureau (BBB) warned consumers to be extremely wary of telemarketing calls and mailers which claim their auto warranty has or is about to expire.

BBB advised that the deceptive solicitations could persuade car owners to purchase an extended auto service contract of questionable value.

BBB said it had seen a considerable spike in both complaints and inquiries from consumers who state that they received misleading mailers or high-pressure telemarketing calls claiming their auto warranty was about to expire.