Subway Charged Me Wrong for Two Wraps and Ignored My Issue

Every time I place an order from Subway, they can’t seem to hear me—even when I speak loudly. Once, I even found a hair in my food and had to ask them to change it. I always order the same thing, but the price is never consistent. When I ask for a price breakdown, they pack my food first and then make me wait 5–10 minutes to be charged—and sometimes they even give me the wrong change. Today, the tablet showed I was being charged $29.29 for two wraps. I showed the staff my previous receipts, and after recalculating, the total came to $23.10. I handed over $50.10, but she gave me a receipt showing $27.00. How is that even possible?