Lidl complaint: Acting manager rude and angry

While checking out today, there was a question regarding a discounted item (buy one get one half off). When asked, check out clerk called the acting manager who came to his position, addressed my wife rudely for questioning the application of the discount, proceeded to tell us what the amount should be and then pointed out that it had been applied. During the exchange, the two customers immediately behind us also indicated that they too had the same product and were interested in how the discount was being applied. The manager pointed at the customer immediately behind us and asked Are you with them? She was not and was informed that the ‘manager would deal with her after us. Finally she came around to our side of the check out counter, pointed to the screen and said You received the discount, pointing to a negative value but the item it was applied to was not visible. Based on her attitude and behavior, we requested to see the Store Manager. She informed us that she was the acting manager. We requested her name and were told that she did not give out her name. We finished our transaction, verified that the discount was indeed taken off the products in question and left.