Hi there @Cogcass, welcome back to our forum and thanks for you.
I'm sorry to see that you are having issues with your landline being engaged permanently. Have you been able to check our service page here to see if this is due to any known issues in the area. You can also run a fault test with the equipment to see if this helps by signing into the page with your My VM details.
If this does not help, it may be worth checking our landline support page here to see if this helps resolve the issue.
If you still need help after checking this, please let us know and we will be happy to help.