Unexplainable LAG

For some reason i get 300 - 400 ms the whole game long... no matter what client i use... My normal ping is between 190 - 210 (South African playing on EUW because it is the closest server) but all my SA friend have been complaining about the similar problem. I have contacted my ISP and they told me everything is fine on their side and on my internet line.

So plz RITO fix this?