So clearly we can see from the pictures that it’s not a great job, the issue you have is it’s gone legal already. (or it’s been going on some time and the legal route has prompted this thread).
DO NOT IGNORE THE COURT DOCUMENTS.
If you do, you will be ruled against and you’ll have to pay plus costs.
The issue you have is that quality of work is subjective when it comes to the law. It’s not as cut and dry as you think, which is why I was asking what form the legal process has taken.
What is important is that you reply to the court in a clear factual manner removing emotion completely.
Document the complaints in detail and in length. Then get an estimate or two of what it will cost to rectify the problem and include that in your defence. It’s effectively a counter claim. That should get the ball rolling.
