Getting -14lp, because my premade left.

So me and my premade went in a flex game, he instantly got bug splatted and couldn't rejoin. The client told him, that he has no internet while we were talking. He could reconnect after 2 mins and 50 secs, the game said reconnected, while on his screen, he was still loading. My team remaked and my friend got back to defeat screen. At the ending screen I saw, that i got -14 lp for that, because he was my premade. It is so unfair, that I lose LP, because he is my premade and the game didn't let him in.