i got suspend for no reason

You want Riot to fix your shitty internet?

As much as it sucks to have an outside source causing the problem like internet, it's still a problem on the customer side. An example is it's hard to decide on a disconnect if it's on purpose or not. RIOT has no way to determine if your D/C was intentional, so they err on the side of caution, and suspend anyone who consistently leaves a game. Fix your net problem, and it won't happen.