Unable to connect SKY HD+ box to SKY broadband since router settings changed to channel 9

[boycat]

Hi

My SKY router kept dropping connection to the internet so SKY changed the channel from auto to channel 9. No idea what that means but they talked me through it. 
Ever since the change I am unable to connect my SKY HD+ box to the internet, so cannot watch anything on demand or search for anything! 🤭

Every other device connects to the wifi without any problems.

I can't get a proper explanation from SKY. They just keep offering me SKY Q which I do NOT want.

Does anyone have any ideas?

Thanks