Dear Sanu,
It happens somes times due to a problem in the system or internet connection break up.
You can contact paisapay department on the nos given below. They are very efficient. You just have to provide the transaction details which shows in your account statement.
022-60003229
1800 209 3229 (for all operators)
1800 22 0288 (Only for MTNL / BSNL lines)
Timing – 10 AM – 6 PM (Monday – Sunday)
Regards
Shuaib