The founders of Skype filed a copyright lawsuit against eBay Inc. and the companies planning to buy the Internet-calling business, saying that damages are growing at a rate of $75 million a day.

The founders’ company, Joltid Ltd., also asked for an injunction to stop the alleged infringement, according to a court filing in US District Court in Northern California.

Skype’s founders, Janus Friis and Niklas Zennstrom, own the technology that drives Skype. They retained the rights to the software code when eBay bought the company for $2.6 billion in 2005. Since then, eBay has showed the software’s source code to third parties, copied it and altered it without permission, according to the complaint.

John Pluhowski, a spokesman for eBay, and Rich Myers, a spokesman for Silver Lake, didn’t immediately respond to requests for comment.