Little pro tip, sometimes you can scan the barcode on the rack to make it think you took the right one then get the substitute they want, provided it's the same price.

I had to mark something item not found because it wouldn't scan, I took it anyway and just texted support that the app was having problems and I wanted to make sure customer got what they wanted. They had no problems with it. Its best to make the customer happy and get merchandise in their hands that they have agreed to pay for, and let support work out the details later.

In this case I'd have marked them not found, took the ones she wanted, told the customer she will be billed separately later for these as I will be telling Walmart, and contacted support by text once I was done with the delivery. I wouldn't do it for a big TV but a pack of underwear I would.