A car hit me and claimed it was my fault...?

The car ahead me randomly slowed down and turned into a back alley without signaling. I did not know the car was turning right and the car began to turn. I was honking and the car did not stop so I swerved and sped up in attempt to dodge the car. Unfortunately the car hit my left side but the driver claimed it was my fault because i was supposedly trying to cut him off. I need to make sure that it isn't my fault and that he was just trying to confuse me. Please help.