ok. I didn't find topic about teachers, so I'll write it here.
I'm looking for a piece of advice...
I started playing the cello in January this year. I had a great teacher, so every lesson was a pleasure! She was sooooo patient, understanding and kind! She is also a director of private music school which I attend and she teaches music in 4 schools, so she decidet to employ a new cello teacher. But this new teacher is... horrible! She is unkind, unfriendly, incompetent (it's her 1st job after studies) and abnormal! She shouts on me on every lesson because my cello is make out of tune after practising and all the time she plays with her mobile phone. I had problems with my index finger (it blocks) and she said that I'm joking and trying to make her angry on me...
My friend has the same problem with her, so it's not my oversensitive.. I don't know what to do. I used to love playing cello but now every lesson is a defeat... I can't go to public music school because I'm almost 16. I want to change teacher but it's really hard to find cello's tutor...
What should I do??? I should give up? Talk with director?
Have someone the same problem?

I think you should find everyone that agrees with you and collectively talk to your director. If that fails, try to find a new teacher, or maybe try a special arrangement with your old teacher. You shouldn't have to hate cello because of a dumb teacher.

A teacher who constantly plays with her mobile phone during lessons is a teacher who needs to be fired immediately: report her.

I really want to and I'll proboably do it because I've got enough...
But, I'm afraid that she will say that I'm lying...

Well I think that if this teacher is bothering you, you aren't going to give as good of a performance as you would with a teacher who actually cared about teaching you and not worrying about how she's gonna spend this fast buck she's making off of you.

If she is playing with her cell phone, what are you doing? Is she not doing anything with you? If the only thing you're doing there is playing like you normally do and have her give the occasional rude comment, why bother staying there? All that you're paying for is to be ridiculed by someone who's not even paying attention to what you're doing.

She can't say you're lying if you get others to help you out. You (with or without a group) should also tell her. Then she can't say she didn't know. Of course, that would be a bunch of crap... the cell phone thing is common sense. But it might not be a bad idea... You could also try writing her or her supervisor a letter, and get as many people as you can to sign... Just more ideas.

My friend has the same problem with her, so it's not my oversensitive..

Then ask your friend along and tell the director together :D