I don't think you have clutch problems. You have the dirty TVA (throttle valve actuator) symptom, no power, no revs etc. If the clutch was gone, then the car would rev but would not accelerate (second gear, 30km/h foot hard down, the revs rise but the car doesn't pick up speed)
After you clean the TVA, take the clutch actuator off and clean it and grease it. There are tutorials on here for both jobs, well documented, and both tasks are do-able with minimal tools. So take a look in the Technical tutorials, borrow or buy the appropriate tools and get to it
These garages you've been to are just trying to rip you off !