Vonage Holdings Corp. (NYSE: VG) has lost another patent infringement case, this time to Sprint Corp. (NYSE: S). The troubled VOIP service provider has been ordered to pay Sprint $69.5 million. (See Vonage Loses Sprint Verdict.)

Like Verizon Communications Inc. (NYSE: VZ) earlier this year, Sprint had sued Vonage for violating patents related to Internet-phone technology. As with the Verizon case, Vonage says that it plans to appeal the decision.

"We are disappointed that the jury did not recognize that our technology differs from that of Sprint's patents," said Sharon O'Leary, chief legal officer for Vonage, in a statement.

Back in March, Vonage was ordered to pay Verizon $58 million after violating three technology patents. Vonage was temporarily barred from signing up new customers, but would eventually win a stay from an Appeals Court judge allowing the company to operate normally while its appeal was heard. (See Vonage Ordered to Pay $58M to Verizon, Appeals Court Lifts Vonage Injunction, and Vonage Wins Stay.)

An Appeals Court decision on the Verizon patent dispute could come at any day. If the guilty verdicts are held up for either of these cases, it could permanently cripple Vonage.

The company has had a hard time cutting quarterly losses and has seen its stock fall to $1.30 from a high point of $15.

— Raymond McConville, Reporter, Light Reading