Founders Niklas Zennstrom and Janus Friis of Skype have filed suit against eBay, arguing that the latter violated a copyright agreement that forbid it from sharing the proprietary code that powers Skype, VentureBeat reports.

Officially, the suit is being brought by Joltid, a company the founders own.

Earlier this month eBay announced plans to sell 65% of Skype to a triage of private equity firms — Silver Lake Partners, Andreessen Horowitz and Index Ventures — for $1.9 billion. According to Joltid, the sale violates the eBay's licensing terms for Skype's technology, which is technically still owned by them.

Joltid hopes to stop the deal and garner statutory damages, estimated at about $75 million per day. It is also suing the venture firms that agreed to purchase eBay's share, as well as the Canada Pension Plan Investment Board.

When eBay first purchased Skype, Zennstrom and Friis attempted to sue the investment banker who brokered the deal — filing suit in the US, Holland and Britain, respectively. They were unsuccessful.