Federal prosecutors in southwestern Illinois say they’re planning to take legal action against a telemarketer who sold extended auto-service contracts. The U.S. attorney’s office in southern Illinois says it’ll detail the move during a court hearing Monday afternoon in East St. Louis.

Authorities aren’t identifying the company involved or specifying the allegations. But prosecutors say they involve illegal robo-calling made to millions of U.S. consumers, who were told their auto warranties had expired or were about to lapse.

Wentzville-based US Fidelis was the nation’s biggest seller of such contracts, and the bankrupt company has been a target of a federal criminal investigation for more than a year.