Makro is shocking in their dealings with returns

I placed an order for adjustable knee supports on promotion on Makro's website 11 January. The 3rd party supplier is RT Beauty. The wrong product was delivered. After many emails and numerous phone calls it was collected 3 weeks later and the correct item was not delivered as requested. The matter has been said to have been escalated - the line given by every call centre agent. Today I was told they do not have a phone number to contact this supplier. SURELY MAKRO YOU VET THE 3rd PARTY SUPPLIERS.