No refund received from Payflex

I purchased an ASR iPhone 16 Pro cover for R649.00 and two car scent fragrances valued at R120.00 each. The total value of the products purchased worked out to R889.00, which I paid using the Payflex 4x instalment option. They took the first instalment of R222.25 upon purchasing the products. I received my products shortly thereafter. Unfortunately, the phone cover which Takealot delivered was not the one which I had ordered. I returned it and was refunded on Takealot. I received a notification from Payflex saying that since my refund of R649.00 is less than R17.75 currently owed, such R649.00 will be used to settle the R17.75 which, in any event, I settled with my own money. On my Payflex balance, I currently have R4.00. I sent them an email to inquire about this, they have not responded. It’s needless to state that I also sent a follow up email, which has not been provided any response. I’m extremely disappointed with the service received from this creditor, to an extent that I’m considering escalating this with the NCR.