Hi there @e-star
Thanks for popping back with the picture. We're just trying to get an understanding of what you are trying to do.
It sounds like you're trying to use the Call Waiting feature to swap between an active and new call - is that correct? Call waiting can depend on the device you are using as well as needing to be activated from your account.
This feature is usually automatically active so if it's not working it could suggest the device you have does not support the feature.
What we can do is remove and re-add the feature from this end to see if that helps - if not, then this is more than likely a device issue. I'll need to pop you a Private Message to go through security and ensure we do the checks on the correct mobile number.
Please look out for a purple envelope on the top right of the page and pop me a reply when you can.
Cheers