My router is TP-Link TL-WR1043ND V1

I flashed an OpenWRT Firmware But add some problem with my ISP,
I followed the instruction on flashing back original Firmware but i can log into the router GUI.
I tried the user and password from TP-Link; the password i set in OpenWRT and my previouse user and passwords,
none of them work.
Any Help will be much appriciated.

Thank you