Since why is a y added on the end of masculine nouns in accustive?

Я не понял, что сказали по телевизору. - Why is there an y on the end of телевизор??? its not feminine... is it?! Also, понял, doesn't the verb понимать mean to understand, or is yours perfective? Also, is that past tense, because I sure hope not. My sentance wasn't.

Иди сюда для ужин. <--- Is mine right too? Come here for dinner, come to eat dinner, very simmilar

Иди вон туда и не возвращайся! - I see all the mistakes, and I get it.

Where the hell is my breakfast?!?! - Где же моя завтра!?!?
I didn't translate it literally. the ".... the hell..." is there because I wanted to practice using же.

Я бежал от волка. - Take out away because it sounds clumsy? And why is волк in genetive?

Thanks for your help