No expiry date on packaging of product

I'm staying in Piet Retief, Mpumalanga. We went for our vacation to Ballito, I purchased Baby Born Food Packs, along with quite allot of Baby Born Products, on the 6th January 2016. As there was no expiry date on the packaging, I expected the product to still be usable. When we came back home from our holiday, I opened the packaging only to find that on the food packs it has expired December 2015, after I opened a packet. It's really unacceptable that you must pay such a big amount for something that has already expired and cannot be used at all. As far as my knowledge goes, its the staff of the involved shop's job to look for stock that has expired and to send it back to the supplier. Hope we can resolve this matter!!!