YOU SAID:

I'm not attending to class

INTO JAPANESE

私は授業に出席していません

BACK INTO ENGLISH

I am not attending class

INTO JAPANESE

私はクラスに参加していません

BACK INTO ENGLISH

I am not in class

INTO JAPANESE

授業は受けてないからな

BACK INTO ENGLISH

I am not in his class.

INTO JAPANESE

授業は受けてないからな

BACK INTO ENGLISH

I am not in his class.