Construction at its worst Northern Suburbs

A builder advertising on Facebook, claims to complete jobs quickly and efficiently. Well where do I start, except to say he promised to build a granny flat (for my sister) for me to live in.... my sister foolishly paid him for everything just before he was due to finish, trusting him completely. She is 70 yrs old and a widow. He took the money and decided to stop working. This was in December. He still has her original plans for her house, she paid him thousands to get the plans approved but never returned. Instead when he left, he took the paint that she had paid for, the barn door and sliding kit that was supposed to be installed, he never completed the ceiling in the bathroom, never finish installing the showerhead. The list is endless... We had to get another plumber in to relay the pipes, as the toilet wasnt flushing properly. Currently my ceiling has pulled away from the beams due to bad workmanship on the roof .... most importantly, he refuses to give her house plans back. He never got the plans approved and when we complained, he threatened to call the building inspector on her as he had built very close to the vibracrete wall... He wont return the items that belong to her and won't reply to messages. I hope that he doesnt take advantage of any other eldetly people out there