Pathetic customer service reaping customers off

We were supporting this business until I ordered a plate of briyani that was advertised as R75 upon delivery I was not at my desk and my colligue decided to pay on my behalf only to find that I was charged R160 with no explanation , I then went to the restaurant to speak to the manager by the name of Brett he just told me that every business has rules and they won't do anything about my matter , How pathetic is that ?,we've been supporting them and this is the thank you I am getting , the worst part the briyani was over spiced very cold and the meat was so hard and dry , I wouldn't recommend this restaurant to any 1 as the service I got was horrible and for the manager to give me such response its shocking