I dont think they pay anything I the article itself it says it’s free to use
The data is free to download. Someone has to host the map data and that’s either a 3rd party provider or self-hosted. Both cost money.
Of course, but that’s not what the previous poster was talking about. They were talking about commercial use of the data.
Someone also answered the hosting question on the golem forum, they do host it themselves: https://forum.golem.de/kommentare/opensource/paketverfolgung-und-mehr-post-und-dhl-wechseln-von-google-maps-zu-openstreetmap/immerhin-laedt-die-post-die-daten-von-den-eigenen-servern/170687,6788315,6788315,read.html