It's not surprising, though it possible is harsh.
The flying school will have had a big financial hit because of an accident like that, so it's hardly rocket science that they are going to be annoyed.
To blame it solely on the student isn't really fair (depending on the stage of their training) however, it's the owners trainset and if they don't want you to play, then they don't have to.
As per usualy with stuff like that, none of here were present, so it's impossible to make a real judgement as there is always 3 sides to any story. Your side, their side and the truth...