Duplicated transactions now my problem to sort out

I made a purchase at your clearwater store on the 27/11/2020 I paid R900 with my Poetry store card and R418.40 with my FNB card. The till slip was not issued by the machine and Lungile who was assisting me called the IT department and they said the transaction was reversed we need to do the transaction again, this resulted in the transaction being duplicated. I called RCS on Saturday and was advised that the transaction is reflecting twice. I had to go into the store to get told its reflecting once on my store card and twice on my FNB card. They could not do a refund on my FNB card therefore the 1st transaction of R900 and R418.40 was refunded on the poetry card on Saturday 28/11/2020. I received an email from the store advising me that merchant services says only one transaction went through yet I was told by the agent at customer services that two transactions went through. I hope I’m not going to be charged interest as my account is over limit due to the duplicated transaction. Someone needs to call me to sort this out. I still have not received my refund on my FNB card either as they cant do it inside the store.