(Bloomberg) -- Minnesota's attorney general filed a lawsuit against CenturyLink Inc. alleging that the telecommunications company engaged in unfair billing practices, according to a statement by the AG's office.  

The suit, filed Wednesday, claims that CenturyLink charged customers higher rates than they were initially quoted and refused to honor the quoted prices. The complaint, which couldn't be immediately confirmed in court records, included two examples of Minnesota residents who say they were charged more than the initial quote, in one case $29.95 a month rather than $14.95. 

"Shopping for internet and cable TV service isn't easy if companies don't give straight answers about the prices they will charge," Attorney General Lori Swanson said in the statement.

"We have been cooperating with the Minnesota Attorney General's Office since its inquiry began and have provided all information requested,'' said Mark Molzen, a CenturyLink spokesman. "We are disappointed that the Attorney General has chosen a press conference to communicate her concerns instead of contacting CenturyLink directly. We take these allegations seriously and will review and respond in due course.''

CenturyLink was accused earlier of inappropriately charging customers by a former employee who claims she was fired for whistleblowing and who sued the company in Arizona for wrongful termination in June. Her complaint alleged that CenturyLink "allowed persons who had a personal incentive to add services or lines to customer accounts to falsely indicate on the CenturyLink system the approval by a customer of new lines or services." Shortly after her lawsuit was filed, the company said it was investigating the allegations. 

Additional cases have been filed in California, Oregon, Idaho, Colorado, Nevada, and Washington. "We are proud to have exposed this massive fraud on consumers, which has unjustly enriched CenturyLink to the tune of billions of dollars nationwide," said Ben Meiselas, the attorney with Geragos  & Geragos APC who represents plaintiffs in those cases and is seeking class action status for them. "We applaud Attorney General Swanson and call on all Attorney Generals across the nation to protect its consumers against CenturyLink."