How to deal with this university lecturer ?

I think you should notify the head of the department (not the dean) that the lecturer cancelled the final, that you weren't notified, and that when you did try to find out the date of the final, you were publically ridiculed in cl. I think you should also mention the fact that she publically uses expletives and four letter words and that such behavior and such language brings down the entire department. Although I think the lecturer's behavior is abominable, I feel that the more professional and straightforward are with your comments, the more you will rise above the low behavior of the lecturer. I am personally appalled at such childish behavior going on in what is supposed to be a higher level of education and I'm sorry for you that you were put in such a demeaning situation. Rise above it. Write to the head of the department. Keep it short. Keep it simple. Keep it professional. It's possible that you won't get a favorable response -- or a response at all. I say that because when employees (the lecturer) behave as badly as the one you are describing, it is usually with the knowledge and condonment of their superiors. On the other hand -- it's possible that no one has ever approached the Head with this kind of complaint. If you do not get a response from the Department Head, then write to the dean, enclosing a copy of the letter that you wrote to the Department Head and explaining that you haven't received a response. (Do some homework here -- be sure your lecturer reports directly to the Department Head, if not, write to her direct supervisor, and then, if you don't get a response -- write to the next highest supervisor. Keep going up the ladder till you get a response). The most important thing is that you treat yourself with the respect you deserve by stating your complaint in a manner that will demand that you be responded to with respect. Again, I'm sorry that this happened to you. It's not right. I wish you the best of luck and commend you for bringing your problem to this forum for advice and suggestions.