Please Guys help me im fucked

Hello guys so lately ive been having this issue whenever i launch league of legends it completely fucks my game so the thing is my internet is perfectly fine ping is like 50ms in every other game but when i play league of legends i launch the client and get into a game it just completely fucks up my internet i dont know what to do anymore its been like this for like 4 days i recently reinstalled my windows i dont know if thats the issue but its not since my windows is up to date so whenever i get into a game my ms goes like up to a 200 or even 1000 and when the game finishes it still keeps going the internet is completely fucked up but when i turn off the pc and turn it back on my internet is fine if i dont play a league game i dont know what to do and what seems to be the problem i tired contacting internet operator they said theres nothing wrong with my internet im completely clueless so if theres anyone whos expirienced this issue and can help me with it please do i would be very thankful. Also ingame i keep disconnecting and reconnecting every 3 seconds and its like this with my internet after the game too so please help me :/ feelsbadman.