Canada's four biggest cellphone carriers could lose their operating licences if a new class-action lawsuit proves they've misled customers about an add-on fee.

A class action suit has been filed naming CTV's parent company Bell, as well as Rogers, Telus and Fido operator Microcell. It alleges the carriers' monthly $7 "system access" fee is illegal.

According to a report in The Toronto Star, the claim came to light in quarterly financial reports released by Rogers Wireless Inc. and Microcell Telecommunications Inc. this week.

"The plaintiffs seek unquantified damages from the defendant wireless telecommunications service providers, plus costs and pre-judgment and post-judgment interest," Microcell said in its quarterly earnings report released Wednesday.

In the fine print, the phone companies say the charge pays for things like government licensing charges, contribution charges to help subsidize residential service in rural and remote areas, and to help pay for new equipment.

But the suit claims customers are being misled by companies claiming the fee is a mandatory stipend collected on the federal government's behalf. The fee is, in fact, an industry creation not required by Ottawa, the suit claims.

The carriers now risk breaching their licences if caught describing the fee as a mandatory government charge.

According to The Star, Canada's mobile phone operators will make more $800 million from the special fee this year.

Representatives from Rogers and Microcell told the paper they have good defences to the allegations. Telus and Bell declined to comment beyond confirming they are named in the suit.

All four carriers said the suit, which was filed in Saskatchewan on Aug. 9, has yet to be certified.