Problems with mother, potential problem with office? [Advice] [Other]

So, my mom called my "language" teacher because I had gotten a bad grade on an assignment. My mom (whom my brothers and father believe has an undiganosed case of bipolarism) talked to my teacher. I had told Mom that we couldn't use hw part that gives us the answers and we could use our addiitonal aides like vocab and the language points. My mom, who does not interpret information well told my teacher that I had told her we couldn't any items for the assignment. My teacher said that was not true and we could. My mom then accused me of lying to her. I tried to explain to her that I had orginally told her(my mom) I could use resources to help me, but I couldn't use the part with the answers. My mom then preceded to call me a liar and starting cussing at me and starting saying other non-friendly things(like she didn't care if I ate and she was going to take away the gifts she had gotten for me and was going to return them) to me.

I expect that I will get called to the office to talk about this tommorow (teachers are close to the office). I am seeking advice about two things: What did I say to the people in the office if I get called to the office? Like do accept what they are going to say or do I try to defend myself? ( the school counselor knows my mother and I have always had points of diversion)

And if the teacher talks to me tommorow do I try to defend my stance ( which I believe is the truth) or do I accept what the teacher says and not put a fight?

Thanks!

If this needs to be moved to another section please move it thanks!