Back in March it was announced that the second largest wireless provider, AT&T, would be acquiring 4th ranked T-Mobile USA to the tune of $39 billion. Pending the merger, AT&T would overtake Verizon Wireless as the largest U.S. wireless carrier.

It’s not uncommon for rival companies to try and keep the competition from creating a monopoly over a given industry, but this time a group of customers are taking matters into their own hands.

Bursor & Fisher, a New York based law firm, has filed arbitration cases on behalf of 11 AT&T customers, citing the merger would violate the Clayton Antitrust Act. The group claim that less competition in the wireless marketplace would lead to higher prices and poor service. The group filed their first 236-page arbitration document late last week.

Arbitration cases are typically reserved for smaller conflict resolutions, but since customers cannot file class-action lawsuits against AT&T this is the next best step for individuals wishing to take legal action against the company. The law firm is anticipating filing hundreds of these arbitration cases through their website FightTheMerger.com.

Customers aren’t the only ones against the merger, however. The Department of Justice, the Federal Communications Commission and rival provider Sprint Nextel have all stepped forward to more closely investigate the deal. In the case of Sprint Nextel, the company even went so far as to show AT&T how to get more capacity from its network so they wouldn’t need to purchase T-mobile.

AT&T plans for the merger to officially wrap up by March 2012.