Three BTOR appointments offered but none confirmed

[#1]

Friends of mine, an elderly couple, lost sync on Tuesday. The voice service was fine, so they reported the problem to PN.
PN said their tests indicated a PSTN fault, and that BT Retail should be contacted. BT, of course, said that the line tested OK, and their ISP should be contacted. Totally baffled and confused, they asked me to help.
Yesterday I went through the same procedure as above, except that on going back to PN a second time they accepted the fault. I understand why these situations occur, but of course it's all rather Kafkaesque to the unitiated.
My concern at the moment is whether there's another 'black hole' looming in the system.
At the end of the conversation with the PN agent at around 3:20pm, he quoted three engineer dates, all of which were acceptable. I was told that a text would be sent within about 2½ hours confirming the appointment, but no text has been received, and the ticket has not progressed beyond

Quote

Date of engineer : No siebel access 3 requested dates are: Friday AM Friday PM Monday 20th AM. Fault reference : Not able to generate on the outbound call. SFI pool to confirm to customer which was booked.

Ticket: 79917597

[#2]

Hi 4C,
I've tested and raised that for you (them?) and booked the appointment for tomorrow morning as I'm glad to say it was available. Hope the engineer gets things sorted for them. Ticket's been updated to reflect that as well.

[#3]

You're a star - thank you Matt. 

[#4]

Oh dear oh dear. 
I checked the ticket about 2:30-ish on Friday, and noted the comment -

Quote

Rejected clear, will monitor for AA.

This seemed a bit odd, as no engineer had phoned the customer, or been to the premises, and there was still no sync.
The agent I spoke to didn't seem to know what the comment meant, but said that BTOR had attended the fault. I assume that the 'rejected clear' means that BTOR passed back the fault as 'cleared', whereupon PN said 'oh no it isn't'. 'Will monitor for AA' remains a mystery.
Anyway, another appointment has been made, for Monday 20th, 0800 - 1300. Fingers crossed... 

[#5]

Good news. 
This morning, engineer cleared fault in exchange, then visited customer.
Thanks gain, Matt, for getting things moving on Thursday.
Any chance of finding out what the actual fault was? I'd be interested to know.