CHARLESTON, W.Va. -- The state's public utility watchdog has joined FiberNet in asking the state Public Service Commission to reopen its decision to approve Frontier Communication Corp.'s purchase of Verizon's landline network in West Virginia.

In a letter filed with the commission Thursday, the PSC's Consumer Advocate Division didn't state a reason for the request -- only that it agrees with Verizon that the PSC investigate Frontier's operating system.

Last week, FiberNet, which uses Frontier's landline network, alleged that Frontier's operating system was causing numerous problems for customers.

Frontier has until today to file a response with the PSC.