The problems I have faced with sbi unipay-
I have paid almost 10 lakh cc bill through it using my hdfc platinum dc but not a single time my money has been debited and showed transaction failure. But what I have faced is I made the payment it showed successful paid. Money also get credited in my cc. Then after some time I open sbi unipay it shows transaction failure on that particular transaction. Show I searched about this and found out a guy in the reddit for which he has been also facing this same problem. But in his case the transaction that got debited from his account got reversed in 4 days but his cc transaction was not reversed and then after more 10 days his account got debited again for the same amount. So I think better to use Navi app for bill payment as it has a better support team unlike sbi unipay (do not have any support team)