Ok I'll try to put this as short as possible (You can read my posts over in the HVAC on what has been going on for long version)

Ok the kitchen light was a recessed 4 tube bulb ballast ,I framed in the recess and sheet rocked in. We then put 4 can led lights in, daisy chained them in. I installed a dimmer switch , which the led lights are rated for a dimmer... Has worked perfectly now 9 months.
Ok a week ago had the insulation removed from the attic , while they were up there they had bumped 2 of the can lights and they were hanging down about 1/4 -1/2 inch . They left , next day had the HVAC system replaced ok. Now the Insulation guys are back to air-seal and blow in insulation.

Now to the problem ! While one guy was up in the attic air sealing/cleaning up more of the insulation they didn't get from last time. The other guy is here in the kitchen trying to get the can light fixtures to stay in place and then screw the led lights in..
He finishes up and goes back up into the attic , I walked into the kitchen and turned the lights on , only 2 of them come on.
Start with light #1 is on, 2nd one in sequence #2 is out , 3# is on , and then #4 is out.

They don't have a clue, so they call an electrician (actually is a HVAC guy, but does electric too) they clean up their mess and leave telling me the electrician will be here shortly.
He shows up 4 hours later, first thing he does is crawl up into the attic and checks wires etc, says there is only 103volts should be 120. Next he did something up there and I heard a pop noise, he said he pulled a wire out and it tripped a breaker, so I go out to the panel , no breakers are tripped ! Now all 4 lights are out, with the switch turned off he did something up there and it was back to only 2 lights working when I turned the switch back on.

Ok he comes back down and says its gotta be the switch , as soon as he sees that its a dimmer switch he says thats the problem.
He removes the switch (stilled wired) checks the circuit and says its not getting a full 120 ,he says its definitely is the switch. He then removes the switch and checks the wires and says it has 120 now. He touches the the wires together BUT still only the 2 lights come on.

Its now 9 PM he needs to go home , tells me to get another switch and he will be back tomorrow after 5PM and will try the new switch ???

It had worked fine until they were up there moving stuff around cleaning up their mess that should have been cleaned up last week when they were here for 6 hours that should have been here only 4 hrs according the owner of the Insulation place...He's pissed too...

Can someone chime in on what to do ?

Sorry for it being long , but trying to set the picture of whats going on ..