Shares of Vonage Holdings Corp. (NYSE: VG) plummeted on Friday, after a federal judge issued a permanent injunction against the firm, barring it from using technology patented by Verizon Communications, Inc. (NYSE: VZ).

Claude Hilton, a U.S District judge, said that the techniques Vonage used to connect internet callers to landline phones violated the intellectual property of its rival. The judge indicated he would sign the order after 2 weeks time.

Shares of Vonage plunged in afternoon trading, losing 25.43 percent, or $1.03 to reach $3.02 on the New York Stock Exchange.

The firm was found guilty of infringing on the technology at the beginning of March, and was also ordered to pay $58 million to Verizon for infringing three patents. In addition, it was required to pay royalties on future sales.

Vonage said that despite the injunction, its business would not be affected because it would switch to different technologies.

We are confident Vonage customers will not experience service interruptions or other changes as a result of this litigation, Chief Executive Mike Snyder said in a statement.