Poor Pioneer foods 'customer service'

I am very dissatisfied with the supposed 'customercare', I made a complaint over a week ago in respect of whole grains found in the Weetbix which hadn't been threshed an a box of Otees which was half-full. I still have not received a voucher for the replacement items. It seems upon purchase one must retain the slip - as if you are going to anticipate a faulty product. The myriad of questions an photos and interrogation call, has yet to surfice. So I've paid for something I wanted a week ago and now I must - wait?