flat black paint????

My only complaint from making a car flat black, was it looked really good - for about a week. IF you clear coated it, it wasn't flat anymore at all, and if it got dirty it was impossible to clean. If someone touched it, it put grey lines in the paint like suede, then you'd need to wash it again. Maybe it was the paint I used, but I would love if there were a way to keep it clean.