If you have no other option than going back to the dealer, tell them no mo dinero and do the procedure the correct way by spending the appropriate time and fluid it will take to fix a routine maintenance job. Don't let them tell you it needs a master cylinder or clutch.
I had the problem the other day. I got the bike out after having sat for a while, to take to get a new front tire, tire and for Pennsylvania inspection. I had no lever action at all, it went right to the bar and didn't disengage the clutch. No amount of pumping did anything. I was able to get it started in gear, with the lever pulled in, and was able to ride. The clutch began to work. I suspected a little dirt in the line, and air. I changed the fluid last about 2 1/2 years ago.
After installing my tire and inspecting the bike, we took the cover off the reservoir and I saw some dirt. He vacuumed it out, and then fully vacuumed the line with fresh fluid. It's working well now, and still is after two days.
So he cleaned it out, changed my fluid, and they did not charge me. It's why I go to him. He is a good mechanic, and honest. I just wish they were a Kawasaki dealer, I would have had my front tires pressure sensor changed under warranty. The sell Suzuki, Yamaha and KTM. I hesitate to do it at the Kawasaki dealer, since when they replaced the rotors, or tire sensors in the past, they destroyed the heads of the caliper bolts. When they were done with them, they looked like they used Torx bit.
I'm hoping I just had dirt and air in the system, otherwise I will be changing a cylinder soon.