Absolutely dissatisfied with how a complaint was handled

Absolutely dissatisfied with how a complaint was handled by your customer service department and the Trade route branch. I purchased 25 x 1litre milk of which to later discover that these are all gone off despite the expiry date not being reached yet. I want to return all 25 but I was only offered a R250 gift voucher. This does not cover the cost of the 25 milks and Woolworths does not want to take any responsibility for this or their actions.