IT work gone wrong

I took my company laptop in for a quote to replace a screen. They broke my keyboard in the process of the quote and decided to replace my screen without my concent. I signed the laptop out and collected my laptop after rejecting the quote. Now they harrassing me to bring the laptop back to place my old screen back. And also apparently forgot to charge me R300 for diagnostic that we did not agree on. They sent me a Customer repair form with no fees charged. They even showed up unannounced at my workplace with the Police, puting me in a very embarrassing place. Im receiving calls that i decided to decline now. I even went to the police my self and they advice me to get a protection order against them. I did not steel or do anything wrong and it was their fault for fixing the laptop and not charging me for diagnostic or letting me sign out and take the laptop. They did not do their work properly. Im refusing to take my laptop back as im scared they wil do something out of spite to it. How will they restore it. It was a broken screen and a keyboard that worked. Its now a working screen but a broken keyboard. How can i trust them to even touch my laptop again.