chimera I was having the air conditioning serviced by a mechanic and they got a bit of the air conditioning belt stuck in the timing belt. It jammed.
Need to take the valve cover off and see if the lifter bucket castings are broken or not
If they are not broken it only needs a valve Job which would not involve removing the block and be a lot less work
Side note... if the mechanic effed it up? Why are they not fixing it for you?