NPS — acknowledgement id is pending for confirmation from payment gateway

Address: New Delhi, Delhi, 110009

I reach the payment gateway and after reaching there it gives the error of set transaction limit although i have already set the limit and when retire to open the registration form to make payment, i get the message "registration against this acknowledgement id is pending for confirmation from payment gateway. Please try again after sometime." i got this message on 24 march, today it opened and same thing happened again, please help asap, as the financial year is about to end.

If required i can share required details.