Steep unexplained price increase!

I dont understand how the pricing works in this place! One week I went to go buy an 8 kg Trustee puppy food which priced R179. The next week I went to get the same food and shockingly the price was suddenly R219. That is a price increase of R40! When I called Headoffice they could not explain this to me. Apparently the change of packiging was the reason for the steep price increase. I have found ****a shops where we stay that doesnt even order this food in the bulk quantity that Kaap Agri does but yet their price stayed at R170 even with the change of packiging. How can a place like Kaap Agri who orders in excessive bulk put up their price so much and then cant even explain it decently?