Bad customer service

On 15 August I made a purchase as I had vouchers loaded on my smart shopper card. When I paid I noticed that the voucher did not deduct the 15% as the voucher stated. I made a enquiry in store and they emailed the required documents. They then sent me an email that I purcased the wrong product. I sent a complaint on 18 August and sent the document proving the product was correct and that it was due to the packaging that they rebranded and that the barcode changed that the voucher did not go through. After about a month of back and forth they said that I would be refunded on my smart shopper points with the amount I'm owed. That was a week nd a half ago. I was promised that it would be I on 26 Aug but still nothing. This i totally unacceptable and frustrating. Today is 1 September and still my problem is unresolved. I have to send emails or I will not get any feedback. The other problem is that they do not give me an option as to how I would like to be refunded as in the consumer act. Totally bad service from pnp. No wonder checkers is taking over all the space left by your closed stores.