Vodapay Vouchers ****

I received a notification from the Vodapay app for an extra 20% voucher for Roccomammas. Go to the app and only get 12% extra. The Picture states 20% but when you try to check out, you receive less. Chatted to an agent (Mpho) who states that the checkout is always correct and that the Thumbnail Artwork is not correct. So, basically, the Notification and Artwork are incorrect? Seems ********* to bait and switch people. If I blindly checked out the voucher without checking the math, I would have been ******. I checked a few other Retailer's vouchers on the app, and they were all giving less discounts than stated by the thumbnail pictures. Please assist to update your App Vodacom.