LITTLE ROCK, Ark. (AP) – Windstream Corp. has filed a federal lawsuit against Verizon Wireless, alleging that it was overcharged $7 million for use of lines now owned by Verizon.

The court action filed Friday says that Windstream and Alltel Corp., both based in Little Rock, had a pact in which they exchanged calls placed by each company's customers. Alltel has since been purchased by Verizon Wireless – a joint venture between New York-based Verizon Communications Inc. and Vodafone Group PLC of Britain – thus it is named in the suit.

Windstream alleges that Alltel made billing errors that resulted in an overcharge of $7 million. Windstream says it has paid the Alltel invoices under protest and, this year, has discounting its payments. The suit says the overcharges began in 2006, when Windstream, a broadband and traditional landline phone company, was spun off from Alltel.

The lawsuit also asks for attorney fees.

Scott Morris, a spokesman for Verizon, said the company received a copy of the suit Friday and lawyers were reviewing it. He said the company had no further comment.