Worst experience with Magma security

Yesterday I was a Supersave(Pietermaritzburg). At the exit point of the store i forgot to take out my till slip, that was because the security were too busy. When I was out the Magma security asked if they saw my slip i said no. I gave the other security from a different company (RZS) my slip. Magma security continued talking telling me i think I'm special, why am i not producing my slip. We exchanged words. He started chocking me(held my neck tight). I reported the incident to his superior nothing was done. I made a mistake not to produce a till slip however there was no need to lay a hand on me