Pathetic Service from Store Manager

We visited Thohoyandou this passed weekend, as loyal customers we waited since 8.45am till 9am when the store opened. We ordered a meal to the value of R435.70 which came with a free 2 litre cold drink, they did not have anything but Coke in stock as per the waiter Mashudu however we did purchase another 2 litre Coke. Unfortunately not everybody drinks Coke so we brought in a 2 litre Fanta G**** which was still sealed. The Manager (Rudzaan) was notified about this and approached us very rudely and abruptly telling us we cannot bring other drinks into the store, he then says we must close it and he is \confiscating"it until we are done. We refused for him to do this as his staff said they were out of stock ad we had already purchased two 2 litres in store which we were consuming. He then tells us that there is stock of other cold drinks but did not bring them to us. We find this service very pathetic and unacceptable as we are paying customers and service should come as second nature in this nature of business. We would like this matter dealt with and to be advised on a way forward. """