Hi
Is it a gsm gateway or an analog gateway?
if it is a gsm gateway , there is a factory reset button on the unit, you can click it and stay for about 6 seconds.
If it is an analog gateway, you can connect an analog phone on the first port of the board, then you can press "**" to listen the IP of the gateway,try to log in with this IP, if still failed you can press "*1*2*3*4" to do a factory reset .
If you need a hand please feel free to add my skype upper.hua
If you means the RST button can't working?
Please press the RST button continue about 7 seconds,when you see the LED flash that means you have factory reset success!
If you need my check please add my skype rick.zhu3