How can I speak to my parents to get my Internet back?

Alright my parents Have a weird idea on grades at school. I play my Xbox I get Bs. They got pissed so they took it away. Now I have Ds. In no way did I mean to do that but I guess it was lack of entertainment. They get super pissed so now they take the whole Internet away. Funny thing is that most of my teachers email us the ignments so now I have Fs. I tried to show them that I need the Internet but they're parents they don't listen. My mom thinks Microsoft Word is a videogame. I'm not joking I actually got grounded for that. I need a way to talk to them. My teachers won't tell them cause they don't think anyone can be that stupid. Whenever I try to reason with my parents they take more things away. They blame me for bad grades and say think that taking away these things helps but it just makes it harder to fix them. I'm getting pissed and they just think I'm addicted to videogames. What should I do?