As a rule, DHL promises to deliver domestically within 24 hours; if however, the
sender and the recipient are more than 500 km apart, the transit time is up to 48 hours.
This is only a guiding principle and not a commitment.
DHL is only obliged to deliver within 10 business days.
As a rule, a complaint about the transit time can be filed within the time frame;
that can be done either by e-mail to service[@]cbc-logistics.com or by telephone
on +49 6445 25771-20.
The same applies to parcels Weltpaket Economy/Premium, whereas here longer
transit times are natural and should be taken into account (see DHL transit times by country HERE).