Scam artist or very bad businessman?

Why do people always think they can scam you and get away with it? We contracted GUTTERFRIENDS to repaint our roof, something we have been saving for a long time. We immediately paid the 70% deposit and the work started. 15 years guarantee. On day 1 they started spraypainting already, without prepping the roof. My husband stopped them and they got a small HP machine and pressure washed some of the roof. The owner Derrick came out and apologised stating a misunderstanding. We went through the quote and the scope and agreed that the roof extensions must be white, and that the gutters do not form part of the quote. On week 2 of the 2 day job, they did not return. After numerous calls, Derrick advised my husband that we need to cut a tree that was blocking one corner before they come back and finish. We arranged to have the tree cut and advised them to come back. Two days later we finally got hold of them again, Derrick advised that the sides of the extensions are not part of the quote and will be extra. The quote clearly stated all barge boards and my husband argued why would they sand it of and only quote on painting the front. Derrick advised that he would only return once we pay him the balance. Clearly this was not an option as after all the issues, he will most certainly not return. We are sitting with a half painted roof where the previous paint job flakes are seen, damaged gutters, overspray on our carport and paving and no means to continue. People like this must be shut down and do not belong in business. If GUTTERFRIENDS cannot even honour completing a paint job, their 15 year guarantee means nothing. The photos shows the "great workmanship"Please share this and warn everyone you know against them, as you will lose your hard earned money.