The U.S. Federal Trade Commission has accused internet service provider Frontier Communications of charging “high-speed prices for slow services.”

The Commission therefore calls on the ISP to substantiate its speed claims.

The FTC accused Frontier of failing to provide many consumers with the maximum speeds they were promised. The speed customers received was often below what the ISP advertised in the plan they purchased.

“Frontier lied about its speeds and ripped off customers by charging high-speed prices for slow service. Today’s proposed order requires Frontier to back up its high-speed claims. It also arms customers lured in by Frontier’s lies with free, easy options for dropping their slow service,” Samuel Levine, director of the FTC’s Bureau of Consumer Protection, said in a statement.

The FTC said it filed the proposed final order with the U.S. District Court for the Central District of California after it was approved 4-0.

The Federal Trade Commission enforces civil antitrust law and promotes consumer protection.

The agency investigates issues raised by consumer and business reports, pre-merger notification filings, congressional inquiries, or media reports.