Management doesn't care about customers

I have been to the place a few times. My husband and family have been customers for the longest time. On the 24th January we visited the place and had some drinks. After a while when we ordered again,my ****tail wasn't tasting the same. I told the waiter,he took it to get fixed, when he came back it was worse. I told him,it now just tastes like Sprite and nothing like alcohol or how it first tasted. My husband went and took it back which then was fixed. My sister in-law had the same issue, where her ****tail just tasted like juice. They refused to exchange it The manager came and told us that it's supposed to take like that cause she took to long to drink it. We showed them when we paid the bill because we were about to leave,it was less then 15 minutes. He further went on saying why she never complained from the first sip. It clearly showed from the glass there was about 2 or 3 sips as she wanted us to taste. He refused and become very aggravated and rude. My husband asked asked to see footage of how long she had the ****tail. They went , never saw the footage,they called security to through us out. Is this the way to treat customers? We paid over R2000 and this over a R60 ****tail.