Account sale refund still not reflecting

I returned some clothing that I bought online on 15 December 2019. I returned it at the Haasendal Gabbles branch in Kuilsriver. Their system was offline at that time but the cashier said that as soon as it goes online then the credit/refund will reflect on my store account. 4 days later and it still doesn't reflect. The refund/return slip is valued over R1200. I need Mr Price to take that return off my balance owed to them asap. I do have the slip I received from the store.