However much this is distressing for you, my advise would be to relax and have a good drink. They have no complaint against you that would stand up to any court, any evidence of any problem has now been removed by them. I acted for some clients a few years back in similar circumstances, my evaluation was to get in contact with the electrician who carried out the works first, this they did and the electrician requested that I was there on his visit, we got on really well, and exchanged experience and knowledge after which he corrected his mistake and we shook hands. He was happy the client was happy and I lost out on some small remedial work, but very happy that the system worked in favor of the client.