It could be a quite few things.
It sounds to me like there's a problem with the pressure plate possibly being faulty, or incorrect one supplied. Either that or the wrong clutch plate was supplied. There CAN be a whole bunch of other possible causes ( contamination, incorrect flywheel machine, pressure plate bolts not tight / broken, and so on ) but they are less likely to be the problem. Also worth checking is the clutch pedal adjustment to make sure you have freeplay.
After that, there's only one real way to find out !!