Hi andystokes,
A warm welcome and thanks for posting on our community forums. Sorry to hear that you currently have no dial tone, and a crackling sound on your line.
We appreciate you trying another handset already for us already.
Can we ask if you currently have your landline through your master socket or through your hub?
Also, if you have any extension sockets or other equipment attached to your line, can you make sure you unplug these.
Please let us know regarding the above so we can assist you further.
Kind regards Jodi