Refund for Online purchase

I did an online purchase for Ryobi 650 W 2-Stroke Petrol Generator on the 4th of May 2020 and selected Riversand store as a collection point. I called the call centre to check the order and I was told that it will take up to three days for the order to be ready for collection. As i needed the item urgently, I went to the store(Makro Riversand) immediately and cancelled order. the person who was assisting me in the store online department said the order has been cancelled and the money will be refunded withing 5 days. I then went inside the store and buy the item. After three days, I received an sms saying my order is ready for collection, I contacted the call centre to enquire about this as the order was supposed to be cancelled and the agent told me it was not cancelled. So the person from the store did not assist me at all, he just promised me a lie. the agent said she will request the cancellation and Ishould received the confirmation and the money will be refunded. I waited for a week without receiving the confirmation and when I contact the call centre again. The another agent said it was not done again and she will escalate this matter to the store and promise me that it will be refunded after 48 working hours. I then waited again. after three days when i call them today the order has not being cancelled and they tell me the same story again that they are going to escalate to the store. I am not happy at all as it seems like no one wants to help me to resolve this. to make the matters worse, I've already purchased the item cash from their store but they not helping me. I'm very disappointed and angry because I need that money. it has been three weeks now.