Online refund

I am very disappointed with the service I received from Makro online. I purchased a heater on the 23 of April for some reason I had to cancel the order. Now they don't want to refund me my money. I logged complain with them so many times they are unhelpful. I need my refund today otherwise I will take this email to your CEO Rori to tell him what a bunch of useless people you are . They can't even resolve small query.