Also you can cancel your Deutschlandticket only before the 15th of the month.
And somehow getting a Deutschlandticket not starting at the first of the month is impossible.
It's all around scams and it's utterly embarrassing that 210k people are actually employed in Germany for this. There are people who get payed for implementing dark patterns as a government service to get a little bit more money.
That seems to me to be a direct result of too many actors involved in the creation of the Deutschlandticket actually ebing against this ticket, and so those in favor tried to appease them and created this absolut disaster of a booking process. There is no other reason for this otherwise, and it would be trivial to sort this out by e.g. having a validity period of 31 days, or always going until the end of the month and costing only a percentage. But that would be too easy.
Just get your Deutschlandticket from a more customer friendly reseller.
There are a few that let you cancel before the last day of the month, and even let you add the ticket to Apple/Google Wallet so you don't need to depend on some mediocre app having a good enough day to display your ticket during an inspection.
Ah yes the DB app where it's adviced to screenshot your ticket because it WILL disappear when you get checked and you will be blamed and are at fault...
It's all around scams and it's utterly embarrassing that 210k people are actually employed in Germany for this. There are people who get payed for implementing dark patterns as a government service to get a little bit more money.