Poor complaint resolution from management

This happened at the Sandton City branch. While waiting in the queue at the food tills, staff memebers we’re skipping the queue ahead of customers in order to buy alcohol before the 8pm alcohol sale cutoff. We reported the matter immediately and the manager asked us to send an email to her personal email address. We sent an email explaining the events to the customer service address and the only response we got was “thanks for letting us know”. I wonder why we were asked to email the complaint when we had let the manager know on site.