My prof is accusing me of chatting on an Online exam. I did not cheat. The exam was 30 multiple-choice and 3 short answers. I got all MCQ right, except I made some mistakes in the short answer. In the exam, His concern only on the last 3 short answer questions. he claimed that he cheats from the test bank ( Answer key of the test book). Also, he claimed that I answered one question similar to the textbook; however, this question's answer included only simple mathematical addition of some numbers. This does not show any valid reasons for his accusation. Moreover, during the meeting, he blamed me for choosing the wrong answer for a question. Thus, I am being blamed for answering questions, whether they are right or wrong. and another question was because I answered similar to the test bank as he was like," this part of the question was not in the test bank)
Secondly, he accused me of violating academic Integrity in my online quizzes, and his concern was, "My other concern is that you spent on average 18 minutes on all online quizzes following the first quiz that included short answers, whereas the class spent anywhere between 40 minutes to 2 hours. The majority of students use a second attempt to improve their score on the first attempt." Note: all the quizzes are theory 30 MCQ, except the first quiz was 25 MCQ and 1 short-answer. He sent me an email to discuss, and then during the online meeting, he asks me to do an oral exam." he was like, so I can prove some evidence," and I refused to make the oral exam as it's unfair to be exam orally for something I don't do it. He gave me zero on the midterm and put me under academic integrity. Please advise me what I should do? I have my review of the hearing next week.