Toxic Premade 4's in Draft Mode Pt.2

So I'm first pick and i chose morgana mid... and as soon as i do the 2nd person, who later picked urgot, said that he and his premade 4 buddies would feed if i didn't go support. I didn't go support and urgot proceeds to go mid, screw up my last hitting, take my kills, and generally be a duche in team chat to the point i just ignored him. His premade buddies were talking shit all game so i muted them too, trying to salvage the game. We won due to alot of split pushing on my part and them 4 all roaming around together after 40 mins. At the end of the game one of them tells me I'VE been reported.

So here's the issues:

• I, being first pick, picked a champion and a role which the premade 4 decided they didn't want me to play
• Dodging this toxic team would have costed me a leaverbuster penalty
• All 4 reporting me for their toxicity will eventually get me in trouble for literally nothing
• There is nothing i can do, before or after a game, to prevent me from either having to play with these asshats or incurring a penalty of some sort

Let me wrap this up with the fact that the Urgot was Plat 4, playing with his silver friends, and trolling because he didn't get his way.... Is this acceptable behavior from any player, let alone someone of the higher ranks? And why isn't there a way to deal with toxic premade 4"S YET?