What to do with pushers ??

Hello, I have a question how to behave best when one of you is close to driving, or if “light” braking is allowed? I was on the A60 on the way this morning, so around 140km/h fast, when I wanted to overtake a column of trucks. Before changing lanes I saw a black Audi from even greater distance, which was a little faster (~30km/h) than I was, but still relatively far away. So I set to overtake and drove on the left After I overtook the first truck, however, the Audi drove me very close, better said he drove towards me without slowing down speed and then brake strongly. he then drove at about 140km/h half a meter behind me which made me really scared, because I didn’t even see the headlights, but only the windshield of the backman. I saw the rear of the car and the rear of the car. At first a second honked to make the backman clear, to keep a little bit more distance. However, this was answered with back honk and light honk. Then I broke the overtaking process, I took the foot off the gas and pressed the brake to the pressure point and under constant horned the speed “easy” but steadily reduced and shunted behind the truck against a. The idiot then of course honked back and constantly pressed the light honk, through the rear mirror could ic h look that this was wild in his prolet-car on the gesticulation. He looked kind of funny…… .. after all, he didn’t want to have me in front of him. Was my behaviour allowed???? I couldn’t drive faster at the moment, because I had a car in front of me and the Audi so drove you up so that it would have been too dangerous to keep driving. If this full idiot had left at least 5 m behind me, then I wouldn’t have been so excited, but half a meter was really not very much at 140. It’s not as if I had blocked the left lane at 80 km/h alone, then I could have understood that if you made clear with light and horny times to the frontman, which is in Germany Reichsfahrgebot. I am every year about 30,000km on the road and meet constantly on such idiots which are simply too stupid to keep distance.