Customer Rights Blockage

On November 7th I placed order# 902223 for purchase from Makro Cornubia which included 3 Ace instant porridges. On the 27th I notified OneCart with images of the 2nd and 3rd porridge which have hard dry granules and therefore defective but I was told they have a 7 day return policy. I contacted Makro and they are happt to assist because they have a 6 month return policy for defective goods but OneCart is in possession of the receipt and Makro card used for the purchase so I can't get assisted by Makro. This a direct violation of customer rights, OneCart is blocking me from returning the defective porridge to Makro!