Credit not deducted off of outstanding balance

I ordered a few items from OneDayOnly but one of the items was sold out. I asked to be credited for that item. The credit has been passed and I can see it but it has not been deducted off the amount owing.

The last payment is due on the 1st September but nobody from Payflex is bothering to get back to me even though I have sent MANY emails querying this.

To everyone using Payflex, when you get a credit CHECK that it has been deducted off of your outstanding balance.