Helping disabled friend with phone issues - guidance please

[#1]

OK my wifes friend has contacted us to say she he3r house phone has stopped working this morning.

She has contacted Plus Net via a message/ticket and received a message saying
Test Result: Fail - Fault located at customer apparatus (appointment required)
Description: LOOP CONDITION DETECTED (UNPLUG ALL END USER EQUIP and RE-TEST)
Now the tricky thing is that the friend has to use a voice synthesiser software to communicate so its very difficult and exhausting for her to call plus net directly.  Can someone tell me what you would recommend that is done to test the problem at her end.  She is unable to do the tests but I have assistance from her young cousin - I live 3 hours away from her or I would go around and help.

cheers

[#2]

Hi BRABUS,
The basic checks we'd usually advise are to try a different phone handset if one is available (corded is usually preferable) and to test the phone with any other devices disconnected from the line. If they have broadband swapping the filters would be a good idea too.
Let me know if you want me to have a look at their account as I'd be happy to do so.

[#3]

Cheers Adam,
I have sent some instructions and will await for the little cousin to report back.

[#4]

OK, just drop me a DM with the appropriate username if you feel the need.

[#5]

Hi Adam,
it seems the micro filter was the cause.  They have used one from her BT set up at her old house and now the phone is working phone.  Someone at Plus Net has just called her and also checked the line and it seems fine now.
Thanks again.

[#6]

Thanks for letting me know, I'm glad that got nipped in the bud