Unable to render customer service and to honour the contract

I went to Zeerust branch on the 18th of December to purchase a stove 4 plate for R2399 and I paid R700.00 for delivery by my grand mother in Driefontein and I was told it will take 3 to 4 working days On the 12th of Jan 2018 I phoned spoke to Brian branch manager and he said the delivery person had the car problem and I said to him I will give him until Monday to deliver which was on 15th but nothing until I phone again and I was told by Brian again that their phones had problems and then we agreed that he will refund all my money and even gave my account details but today I get a call from somebody saying they are going to Driefontein to deliver and I was shocked as I was awaiting for money go through my account. I then phoned Brian to find out what's going on where is the money now all of the sudden he says he cannot refund me until he get a purchase slip. I am shocked what does it take to get some service by this shop, if the branch manager himself cannot assist or deliver on his promise to his client.