Plascon does not want to Refund me for deteriorated stock supp****

I Bought a 5l double velvet from Halls Mica in Amanzimtoti. The paint was lumpy , it could not be stirred, it was clearly old/deteriorated stock. I went back to the supplier (Mica) who contacted plascon to collect the deteriorated stock. I was assigned a customer care agent named Kevin +27 76 ********** , who re assured me that after procedure was followed, I will be refunded (R500 odd) the customer care consultant does not take my call or answer my sms. I have taken it up with PR through FB messenger, who promised me feedback. It is three months since, I have no joy, therefore forced to not recommend your product to any of my clients ,but that of your competitors