Bad app

Last week Monday i purchased the specials advertised in the pnp app. After payment was done i received an email that the item was out of stock and pnp was trying to refund me the amount owed. Apparently they tried times to no joy and offered me a code to that amount for my next purchase. Which I've agreed to. Since then no voucher pr communications from pnp. I've sent multiple emails and to date no feedback. I'm absolutely frustrated with the app communication and pathetic service.