Cablevision Systems is suing Verizon for overstating the speed and quality of its Wi-Fi service to customers.
The New York-based cable operator filed a lawsuit at the federal court in Manhattan after Verizon ran TV and radio ads in New York, claiming that its network routers provide the "fastest Wi-Fi available".
Cablevision claims it already offers the same routers to its customers, and has done for about a year.
"Verizon’s claim that it has faster WiFi than Cablevision is false, deceptive and designed to mislead consumers. Verizon has no public WiFi network," Cablevision said in a statement.
"In addition, Verizon’s in-home routers are not faster than Optimum Smart Routers and cost Verizon customers hundreds of dollars while Optimum’s are free. It is not a coincidence that Verizon is making false WiFi claims just as Cablevision is introducing its all-WiFi Freewheel phone, which will allow consumers to avoid Verizon’s data caps and excessive data overage fees."
Cablevision is hoping to force Verizon to stop and correct the advertising, and to pay damages.
Verizon, which reported a net loss of $2.148bn for Q4 2014, has reportedly rejected the allegations
"This is a boldface ploy to promote Cablevision’s latest wireless gambit," Verizon said in a statement. "A third party has tested and validated the FiOS Quantum Gateway router. It offers the fastest in-home Wi-Fi available from any provider."