Standard Bank Refusing to Reverse Payment to a Closed Account

I mistakenly made a payment into an old Astrodon Standard Bank account. When I contacted Astrodon to request a reversal, I was informed that the account was closed over a year ago and that Standard Bank is responsible for handling the reversal. However, Standard Bank continues to insist that Astrodon must facilitate the reversal—even though Astrodon cannot provide permission for a closed account. Standard Bank also cannot confirm whether the payment actually went through, which is extremely concerning. At this stage, it feels as though Standard Bank is holding onto my money and sending me from pillar to post, despite knowing the account is closed. I am highly disappointed with the lack of support and urgency from Standard Bank in resolving this matter.