Worst experience ever

So today I went to checkers degrendal to do my grocery shopping for the week. As normal I went online before hand to see what specials were available so that i can work out my budget because times are very tough at the moment. Happy with the deals I found I drove down to checkers. When I got there, I noticed that the one bundle deal in the image attached, the vegetable deal was not packed together so I scurried around getting all the items together. Once my shopping was done and I had taken all the deals I saw and calculated as I went along. I proceeded to the check out. So from my calculations it should have worked out to roughly R650. So I get there and they start scanning everything and I swipe my savings card and everything amounts to over R900 which is impossible because I know what it should have been. So I show the teller the screenshots on my mobile and they proceeded to call the manager. After some back and fourth the manager arguing with me telling me I am wrong and that the deal isn't available, I show him and he says it is only available online. Which I didnt believe because the fruit and milk deals were available in store. So after much frustration I tell him to remove those items. Only to find out that the total was still incorrect. So I asked that they cancel the order and rescan everything as I know that there is a mistake. The manager then tries to make me out to be a fool so instead of canceling the order he decides he will remove each item one by one from the order to see if I am right. By this point my level of frustration is sky high. So after scanning and removing each item one by one we get to the end and there is still a total of over r200 but all my items that I had infront of me had been removed which meant that they had scanned multiple of my items more than once. Not only did I have to stand there and waiting for this manager man to patronize me by starting over and scanning my items again one by one to show me he only scanned it once but I never even got an apology for the 45minutes of my time that was wasted because he was trying to make me out to be a ****. Not only was the customer service I received absolutely shocking but the false advertising about deals as well. And in all fairness I thought okay maybe I am wrong maybe this is an online deal but then explain to me why is it not stated anywhere online that this specific deal is for online only and if that is the case then why was all the other deals available in store. Checkers degrendal is a bunch of ****** and if no response comes from this I will definitely take this further as not only was this embarrassing and I was made out to be an idiot when I was in fact correct but in a time like this when people are struggling and can barely get buy then I still have to deal with ******. I Normally wouldn't complain about stuff like this but I am not going to leave it here so i hope to hear back very soon.