How to Prevent my Hotmail from dumb mails

i received a mail from my teacher's login that mail was 191kb but when i open it nothing was in it i replied my teacher that whatz that but he replied that he had not sent that mail after that day up to now i am receiving such mails of 118kb-195kb with different e-mail addresses i've blocked many but they are stilling coming with different addresses. i noticed one more thing that mostly when i mistakenly opened such mails i got logged out. i tried my best to avoid such mails but these mail fill my hotmail account and block my necessary files. so how can i stop this. this is very important e-mail address i dont wana loose it.