lol if they refuse to pay that bill, i think you will find the judge wont be happy that the op never contacted to workmen, never gave them the chance to fix it etc, there are procedures to follow.
this was a accident not malicious, the workmen need to be contacted first to put it right or pay for it to be put right - in my opionion.
The evidence would be the damaged section of cable. Pictures in situ. And its physical presence as evidence. Also logs from the panel or photographs again.
The date of the incident and proof of the works carried out by the guilty party.
Some of us have been in this situation before and given evidence.
So in our opinion the system should be repaired professionally and ASAP.
Letting them know is enough.
Ever had to give evidence in anything similar yourself?