One important thing regarding packages in germany, as a customer (as opposed to acting as a company):
The seller has the responsibility that whatever you ordered actually gets to *you*. If you never receive the package for whatever reason, including theft, the seller has to re-send at no cost to you. The seller might be able to get reimbursed by the courier, depending on circumstances and contracts.
Except, and that is important, unless you explicitly allow DHL to put the packages somewhere, without personal delivery. That is called "Abstellgenehmigung".
Once you have given this "Abstellgenehmigung", the seller has fulfilled his responsibility once DHL says the package has been delivered.
So if you have issues with package thieves, do not provide a "Abstellgenehmigung", if you have given one earlier, you need to rescind it.