Johanna has come to my rescue with T-Com. She went to a T-Punkt and asked about my phone. I have not, it seems, cancelled my account in a moment of unjustified faith in my ability to deal with German bureaucracy. They did something or other about the reported Störung on the 18th; now they are on strike. They MAY do something next week, but they are not making any promises.
WHEN IT IS RECTIFIED. IS ANYONES GUESS. BUT IT WILL BE REPORTED.