TalkTalk Business landline problems

It seems at present TTB have a problem with landline calls, not sure if this effects others.
I can dial out to mobiles and mobiles can phone in, but when phoning landlines just get the number unobtainable tone, this has been since yesterday.
Online chat was at first the usual drivel, "unplug micro filter, £166 charge, blah blah blah", then I was told this is a national problem. Still at least they didn't tell my I don't have a contract like the last time. 🙄

My stepmother has the same issue. The person I spoke to via TalkTalk's live chat cannot have been aware of the issue, as they have arranged an Openreach engineer for Wednesday morning. I can see that it is reported on their Service Status page though:

Loss of voice service across South West and Midland regions across UK
Sunday, 14th November 2021, 8:44:37 PM

We're aware that customers are currently experiencing issues making telephone calls off the network.

We'd like to apologise for any inconvenience caused during this time and assure you that our engineers are working to restore service as a priority.

Update 10:10am 15th November - our engineers continue to work with our carrier partners who are investigating the cause of this issue.

The TTB online operator didn't know at first, it was only during the 'chat' that they found out.
Later that morning it worked for one call, then went down again, early afternoon I tried a couple of times to see if it was fixed to no avail, later in afternoon it was working, not sure if it still is.
My 'cases' page showed an update expected in two days, but this seems to be a standard time scale they use when not knowing when something might be fixed.
p.s. anyone got an explanation as to why mobiles can be called but not landlines?

Edited by burble (Mon 15-Nov-21 19:00:16)

My guess is an issue with switching/transmission somewhere within their network.

My stepmother's landline is working this morning, and the issue is no longer reported on the TalkTalk service status page.

I've used the phone several times this morning and as you say seems that it was fixed yesterday.