how do ppl you report stay in your game?

i report this guy for int feeding player is some how gold and is clearly boosted has 0 clue what hes doing and misses everything. Champ select kids still there with the wrong runes and masteries for this champion again. Sure im smurfing but fuck me wasting time pisses me off the most. To the point why the hell can I report someone for feeding and have them still in my game? esp since im smurfing and have a high win rate while this kid loses every game? I dont understand.