Am I doing the right thing?

My partner and I have separated, he was an abusive (mentally) drug addict. My son, who is 6 now sees his father in a contact centre every second week. On these visits my ex is telling my son that everything is my fault and my son is taking it out on me, he bites, punches, kicks, pulls hair, threatens to stab me, the list goes on seriously. Ive tried every form of positive punishment ive tried reward charts etc. But the physical attacks and bad language remain. I am bruised head to toe my throat is in agony from all the times he's tried to strangle me so I am at my wits end as he was never like this before. I have now resorted to taking away all his toys and games consoles about 8 large garbage bags full and left him with only books (which is kinda good as he is really getting back into reading lol) but the behaviour remains. This is only day 2 to be fair but do you think I'm doing the right thing? Should I seek counselling for him? I cry myself to sleep at night because I think I've lost that loving caring little boy I used to have and dread to think how I will handle these attacks as he gets bigger. Any insight would be very much appreciated from this tired and drained mother. ThanksEdited for damn autocorrect via /r/Parenting http://ift.tt/2D0snaE