http://www.nbcnews.com/news/us-news/hundreds-claim-donald-trump-doesn-t-pay-his-bills-n589261
It is a common business practice among developers for them to shortchange their subcontractors when the sub is finished. They typically claim shoddy workmanship and refuse to pay the entire bill. It is usually an amount which is small enough to make it unfeasible to spend the money and take the time to correct. It’s absolutely dishonest and Trump is a master at it.