Don't put in security personnel that are not clearly identifiable & bug customers

This morning went to FL Lifestyle Randpark Ridge. Tax Inv time 8.13am & there were very few customers in the store. When passing the items to the cashier (Blessing - name on Inv), this young guy came & stood in maybe a meter from me & watching what I was doing. I asked Blessing what he who & what he wanted & she didn't respond & he then left. On the way to the exit I saw him & apparently he is security. Not a clue what he thought he was achieving because when I first looked at him, there was nothing that clearly identified that he was security & as security & if properly trained, apparently not, what made him think he had the right to be so intrusive. I frequent this store as well as Hillfox & not experienced this before.