Unable to change SSID or WPA2 Password

Hi,

I have the O2 homebox 6441 router. I tried to change the SSID of WLAN. Unfortunately I wasn't able to. I called up the customer service. They guided me step by step to change the SSID and password. But it did not happen. Then they told me that a technician will call me up and solve this. Today, I received an SMS saying my DSL line is working fine and I should check my end device. I don't think they understood the problem that I'm facing. The problem seems to be with the router. The internet works fine. But any changes i make to the router are not saved.

I am hoping for someone from O2 to solve this.

Thanks