Is it possible to receive a system notification about transaction again?

In the case, when your system doesn't display correct response after received notification, Tpay.com going to send a notification automatically again. Details about automatic resending of notifications are included on site docs.tpay.com.

Is possible also send a notification manually from Merchant Panel. You should find transaction (Transactions -> Browse/Search) and display its details. Next please click the button "Resend" in "Notification" section.