5000 lag fixed on re opening the game

hello i recently downloaded lol again and there is something wrong , in game each 6 or 7 minates or so my ping goes up to 5000 and will not come down , not even for an hour if i stay in game , but once i closed the game and reopened it and it was ok , so now every time i get this lag the moment it starts going up i close the game and open it again and its ok , but the thing is it takes at least a minate for me to do that , and in a 40 min game it happens 4 to 5 times , that is 5 minate afk and sometime it happens in the middle of fight or dragon or .... so it is game changer ,

my internet is not perfect it has lags every once in the while but this doesnt look like its from my net its definitely a game issue or at least i think so , if anyone had this problem and managed to fix it i would appreciate your help on fixing this annoying problem

(( i dont play any other online games so i cant make sure if it happens somewhere else or not ))

i should add that i also have internet limit and i cant re download the game -_-