I was having the same problem from two days, seems like a server issue. I checked the browser's developer console on payment page, saw this error :
failed to open pay.billdesk.com in a frame because it set 'X-Frame-Options' to 'sameorigin'.
I thought to restart the browser with disabled-web-security
and bypassed the sameorigin
setting and then, billdesk payment iframe (page) rendered and I successfully made the payment. This worked for me.
If others still face the issue, try this. It may work. (Once done, restart the browser normally)