Refund

I attempted to buy a phone at Telkom online during the week of 23 May 2018 and I called them three weeks after they told me that the phone I wanted is out of stock and I told them to cancel the application and I requested my refund for the amount that they billed from my account nothing have happened I haven't received my refund, a whole month now have passed and nothing have happening, I always call them and they tell different stories and also inter change me within their departments