expelled from the university seeking advice

I am doing master in mechatronics. actually in first time plagiarism university advised me so i was aware but my mistake unintentionally the wrong file has been submitted by me and that one got plagiarised so according to university it is second plagiarism i tried to explain that the wrong file has been submitted by mistake and i have the original one also but they directly expelled me and student union also not supporting so please help me out . how can they will consider that that is the unintentionally mistake i want my degree . even i have submitted my dissertation after that they had meeting and taken decision please help me and give the advice any how i want my degree please.