How can I connect to my router after a factory reset ?

Hi ! 

I accidentally factory reseted my Zyxel NBG6503 modem ( I thought it was just a soft reset) . I'm trying to configure everything back now on http://192.168.1.1
But to access that, I need to connect my PC or my phone to the modem, which requires a password, as usual. The default WPA2 key written in the back of my modem doesn't work. I searched online, the only other "default" password that I saw was 00000000 which also doesn't work. 
I don't have an ethernet cable (even if I had one, my laptop somehow doesn't have an ethernet port, this is quite an emergency and I can't find an adaptator here in Sweden, so I need to find something else). The WPS connection doesn't seem to work either since the LED indicator doesn't turn on when I press the button. 

Nothing seems to work, so how can I connect to my router ? 

Thanks in advance ! 

Tom