How can you fix a website which is supposed to implement a totally unworkable law which is crazier than anything Lewis Carroll ever thought of? “The Walrus and The Carpenter” is perfectly logical and understandable by comparison. If ten thousand computer scientists with ten thousand assistants work for a thousand years on the website the real problem will remain unsolved. As we used to say in Dixie, “You can’t make chicken salad out of chicken shiite”.
It’s likely a flawed architectural design. They’ll either have to start over or spend a decade straightening it out.
Ask anyone who has ever dealt with GCSS-A.