No broadband - Fault logged 3 days ago - What's happened to service around here

[#1]

I have had excellent service from PlusNet over the years but feel the need to escalate this issue.
Account name is  aquamar - that should be sufficient to bring up the issue but it is quite simple.
Having been stable for a long time, Broadband service to the property appears to have stopped between 2200 on 14th and 0900 on 15th December.
Please could someone in PlusNet take a look and respond because at the moment it feels like noone is doing anything.
James

[#2]

You should have a update shortly.

[#3]

Many thanks for that. My faith is being restored:-)  I did get an update shortly thereafter and an engineer will be visiting next week.
In the meantime, I did some more checks of wiring and somehow managed to restore Internet  in the property earlier today.  I didn't feel the need to look at any stats but it was all stable (email worked and it was capable of playing a youtube video for example, and I left the house for the weekend.  I was even thinking about cancelling the engineer.
Its 2 hours later, and  I have just  tried to ping the external IP - nothing!  Also, unsurprisingly, I cannot ssh in to any sshd services at the property either.
pinging <accountname>.plus.com doesn't work either. 
So,  assuming the router is still switched on and noone has touched anything at the house what could cause the external IP to become invisible like this?  Are there any checks that woudl be worthwhile me asking PlusNet staff to run?
James