Disappointed first time customer

I'm leaving a 1 star because there is no ZERO😡 3 weeks ago this dealership sold me a car that they certified roadworthy, a few kilometers from their warehouse the car started overheating, long story short we cancelled the deal. Now they don't want to give me my refund, everyday I'm told that I will get it but nothing. Is this how you treat customers? I'm not a rich person, I worked hard to save up to buy myself at least a second hand car now this......😭