Dollar General complaint: Manager and coupons

I was at the store at 225 S. Courtenay Parkway Merritt Island Fl on 612 the day your store supposedly had a clearance sale. I spent more time in the store than I wanted to because your clearance items were not marked or not all of them. I had the app on my phone and was told that I could scan items and that would give me the price. My understanding was the price on the orange tag was marked down and then it would be half of that. I had never done this before, so I spent a lot of time scanning items to see if they were on sale. I went to register and the total with coupons came out to be more than I had calculated, so I asked the cashier (who was very helpful) to have it checked and the cashier called the manager, I explained to him my concerns and he started working with the register and making circles on my receipt. He gave me back my receipt and ask for my card and said he was doing returns on most of the items I purchased. So I did what he asked and then I asked for my coupons (paper) back and he said no. He gave me an untrue statement that they would no longer work for me somewhere else and I couldn’t have them back, which is a lie and not to mention I also lost my digital coupons. I know he will turn those coupons in to get reimbursed for that store with those coupons, which is illegal since they were not legitimately used. I don’t usually shop at Dollar General because many times I have had bad experiences using coupons. I was told by the manager that I couldn’t go by what the app said because it wasn’t correct??? Really then why do you have the app??? I spent a long time in the store taking time to use the app to find out the clearance or maked down items because that store didn’t mark the items that were included in this so-called clearance sale. I found diapers that were included in the sale and the app had them in the sale and marked down but at the register, they came up as the price on the app, not half off. So, I want to know why you have an app if the prices are not correct on it, why I was told I couldn’t have my coupons back instead of overriding the prices to the correct amount and be done with it?