New Clutch, slipping sometimes in high gears

It does disturb me. That started after I pressed down real hard on the clutch pedal witu the truck stationary. The other effect was the free play seemed a bit different after that. It requires less pressure to start the truck too.

 

Does anybody know what the knockung sound could be? It only happens when I depress the clutch, sometimes

 

Is the throw out bearing included in an eaton clutch assembly kit? I had an entire eaton assembly kit plus new fork installed.

About the invoice, I am sure the invoice I was shown was for my truck, they mentioned the new clutch to me the day after the sale was complete, in passing, the minute they heard about it in the morning. Of course I said well Its a done deal and that was that, they never tried to get me to pay for it... however I was never informed they would be replacing the clutch when they were selling the truck to me, so the previous owners really had no reason to lie, as I had already accepted their price, and again they didnt really try, like almost not at all, to get me to add anything on to the price (i know the previous owner and I saw him on the lot the morning he was on the phone agreeing to have the clutch done. I have many reasons, sans this clutch going bad so fast, to believe the clutch was replaced. Ill probably be able to get an reciept for the new clutch tomorrow.