I have to go with the majority on most of this. Disconnecting & taping 'hot' wires and then re-energising the circuit is not acceptable practice. SOP is terminate at the source; ie: remove conductors from lugs of source breaker and make safe there.
Reading your starting thread, I take it that your man re-energized the circuit for 'heat' which I take as an energized feed was still present at the RTU.
Was any evidence of the damage offered to you? Pictures, damaged piping, etc?
Yes, it would have been nice if the roofer/HVAC guys called you, and who did what, and when did the damage occur?
Ever work with these guys before? Financial 'wash' possible? (Your service fees vs. the 'bill')
You may also consider the 'bill' as a wake up call for your man, it could have been a lot worse than a freon line damaged if a person was injured or worse.