Sounds like a slave cylinder fault or clutch ? Either way it's a gearbox out job I'm afraid. The release bearing is also the slave cylinder in one unit called a CSC or Concentric Slave Cylinder.

It may be sticking but more than likely, leaking causing the pedal to stay down when pressed. Less likely is the clutch pressure plate has gone and the release bearing pushing through it ? I've only ever seen this twice, once on a LandRover Discovery and the other on my wife's old Pug 106. In both these cases there was a total loss of clutch pedal but they both still had drive if started in gear. If yours has a pedal if the clutch is bled or pumped rapidly I'd put my money on the CSC leaking.

Obviously, get it diagnosed at a garage first and if the gearbox has to come out, I'd strongly recommend replacing the whole clutch kit at the same time.

Good luck with it, keep us updated.

Does the pedal operation return to normal when you pull it back up from the floor? If so this is a fairly common problem on VW and Audi models. I've had this many times before and I've often cured it by changing the fluid. Try that and if it's still the same then as the above poster says, it's a gearbox out job.

I would expect that since the master cylinder has been changed so has the clutch fluid.