A Texas couple has filed a federal class action against AARP in the District of Columbia, alleging the group used misleading marketing to sell its health insurance policies.

The suit, filed yesterday in the U.S. District Court for the District of Columbia, claims that James and Allison Halpern purchased an AARP Medical Advantage Plan in March 2008, after receiving an advertising packet touting it as a “primary insurance plan.” The couple dropped their old health insurance policy. But after Allison Halpern was diagnosed with breast cancer, they learned their new plan only provided limited coverage, and would not pay for the cost of a crucial surgery.

According to the complaint, AARP’s advertising materials did not indicate that the health plan only provided limited coverage. AARP suspended sales of the policies earlier this year when Sen. Chuck Grassley (R-Iowa) opened a congressional investigation into their marketing.

“AARP has preyed upon Plaintiffs and thousands of Americans over age 50 by luring unsuspecting consumers in need of affordable health care to enroll in AARP’s health insurance program,” the complaint states.

The suit accuses the company of violating the D.C. Consumer Protections Procedure Act. It argues the D.C. court has jurisdiction because AARP is located in the District.

An AARP spokesman declined to comment.

A lawyer for the Halperin’s, Jerome Noll, of counsel with White Plains, New York-based Meiselman, Denlea, Packman, Carton & Eberz, said he knew of one other class action filed against AARP. That suit, also filed in D.C., targets United Healthcare as well, which partnered with AARP to sell the policies. A legal team from Venable including partner William Coston represents AARP in that case.

“We believe there’s a stronger case against AARP,” Noll said. “We allege that AARP’s marketing was deceptive and therefore in violation of the D.C. consumer protection act. [The Halperns] did not receive marketing materials from United Healthcare.”