Most probably the problem is with bill amount. Nothing to do with SBI VDC.It's failing. HDFC Swiggy card payment on SBI Unipay and Canara Setu using SBI VDC (Rupay) is failing.
Paid 4 other card bills today using the same SBI VDC. This alone is failing.
Check exact amount due in HDFC mobile app >> Menu >> Pay >> Card >> Select Card >> See Total Amt Due. Pay exactly same amount. Ideally it should go through.
If still facing problem then dm me.
(Recently HDFC has restricted how much amount we can pay. The window may not be wide enough)