The Hokrala Corp represented a force known as the "Supreme Powers" and attempted to sue Torchwood for mishandling the 21st century and improper maintenance of the Cardiff Rift. Every year after 2000 they would send a writ to shut Torchwood down. (PROSE: The Undertaker's Gift) They sent one writ shortly after Torchwood Three had to deal with Sally Blackteeth. (PROSE: Something in the Water)
Eventually, they turned to more drastic measures. They started sending materials through the Rift to 2009, causing damage to space and time. This attracted the attention of the Already Dead, who had set up a time bomb to activate when the Rift was opened. They also sent an agent in person with a writ which was infested with Xilobytes. The plan was that Jack Harkness would be infested and would die, leaving Torchwood unable to stop the bomb.
Eventually, the Undertaker's Gift was activated, but Jack Harkness was able to get the help of a Vortex Dweller to repair the damage. The Vortex Dweller also sealed up the Cardiff Rift in the 49th century, stopping the Hokrala Corp from any further meddling in the past. (PROSE: The Undertaker's Gift)