5/6 games Intentional feeder

Started the day at 70lp Plat 1 with 2146 mmr which according to op.gg is Diamond 4. 6 games later I'm now 8lp 1954 mmr. I had an intentional feeder or greifer in all of my games. The only game I won was because the greifer was on the other team. I finally won a game and I was excited to try and get back to 70lp with the hopes of getting into Diamond. Unfortunately the very next game my adc left lane to try and steal the first crab on the map from me and when I pinged him back and smited it, he told me, "enjoy your loss" and proceeded to run into bot tower giving swain a free kill. Second crab spawned on map and i pathed to it directly out of base only to have the adc run towards it again and try to steal it from me. I smited it away and he of course in turn ran into bot tower for the rest of the game. He even explained to my team that it was my fault for making him int because I stole his crab. I'm not at 8lp Plat 2 mmr and no longer have a 70 percent win rate. I lose about as much lp as I gain and I no longer have the mental fortitude to climb the ladder for the day, but I can't get off the game feeling completely defeated by something that was out of my control.