2003 Peugeot 206 Clutch cylinder

Engine Mechanical problem
2003 Peugeot 206 Manual 140000 miles

Hi,
I recently took my car into a garage because the clutch felt very loose and I was unable to change gears. If I pumped the clutch for a couple of minutes the clutch resumed its normal function for the rest of the day. Each morning I had to pump the clutch for it to function properly so I could put the car into gear.

I paid  £90 at the garage to have a replacement clutch cylinder fitted as I was told that this was worn because the clutch appeared stiff.
Two weeks later and the same problem has happened again.
I have taken the car back to the same garage who now inform me that the whole clutch needs replacing.

I was under the impression that the clutch functions through hydraulics. The fact that I have to pump the clutch for it to function properly leads me to believe that somehow air is getting into the system.

I can't understand how replacing the clutch is what is needed.

Would it be reasonable to think that for the exact same problem to reoccur only 2 weeks later means that the job wasn't done properly in the first place? Maybe there's still a leak on one of the cylinders or the cylinder was repaired instead of replaced? Or that the diagnosis wasn't correct in the first place?

Please help me by explaining more.

Thanks, Maria