Never purchasing from pnp bottles app

I made a purchase on the pnp bottles app on 23 April. The product was available to select for purchase. Upon debiting my account I got a notification saying the product is out of stock but the app never allowed me to substitute. I made numerous requests to pnp as to why I did not get a refund. They told me it takes 10 working days but it has been a month and I have still not received my money back. I then forwarded my banking details to a pnp consultant who advised she sent my details to the refund department but still no refund has been made