Username & Password for VMG8924-B10A

Basically I wanted to forward a specific port on our router, but we've been unable to log into our router and what I wanted ask is… What is the default username and password?

I've already had a look on google, but the ones I had tried, didn't work.

Any help would be appreciated! Oh and it isn't written on the router itself, all that is written is the network names, the wireless key, the mac address and the serial number, but no username and password. 😕