Selling expired items

Hi, please note that the manager of the Garage called me 23/11/2017 @15:24-pm with this number ********** 409- I feel threatened, he is shouting and telling me that he did not get an open cold drink from me. This is clear that when I returned the coca cola 500ml he did not take a lot at it or attend to the matter as a manager. Due to his shouting, I hung up the phone, and he called again, I told him that I don't see where this is going instead he's questioning me and yet still remember the incident. I hung up again and he sent me an SMS. On the sms he said, he disagrees with my statement, I can lay a charge for this if I don't have proof. He was there, he remembers the incident he said, and what proof can I bring? An yet tells me to come over, that won’t happen. He is rude, arrogant and doesn’t know how to talk to people and customer satisfaction is not one of his goals.