Payflex double standards when it comes to payment

I am meant to be receiving a rather substantial refund as I returned items to the merchant and the merchant refunded to my Payflex account.

It is over a month and I have emailed Payflex inquiring about the status of the refund and no response.

I phone and the automated message says they are busy.

I is rather unfair because if I am late for a payment they charge me interest.

I would like my refund with interest for withholding my money for over a month because that money is needed elsewhere and I am being charged interest for not paying when I was relying on that money coming in.

Please pay back my money with interest.