Some of the fees are indeed then enforceable IF the Betreibung/poursuite actually finds in their favour ie that you do owe them money. In this case the debtor ie the one owing has to pay the reasonable cost of the debt recovery. This is not the same as all the figures listed in the letters of the debt receovery company but will include the actual cost of the betreibung/poursuite plus some of the other costs. If the court finds these costs unreasonable the court splits them as they see fit...