We all knew attacks would come. I don't think anyone is surprised about defects in quality of third party sub-contracted work.
I must agree the 3 party quality. Almost nothing letf from original code.
But be noted, they fail the mission and cost nothing.
Attacks actually prove that they take exchange serious enough to attack and try to gain something.
Maybe not good choice of contract coders. But in future you should still considered professionals do some work for you if necessary.
Nice to see a comprehensive post Halibit and that you managed to sort things out.