The installation fee does not need that there is actually somebody coming to you and install all the stuff, but it is a fee for the (internal) setup and activation of your line together with sending the device to you. This also includes that a technician will visit you free of charge in case the self-install does not work - but it is not a must that a technician visits you.
Secondly your initial invoice will most likely contain the base fees for the next month as well as the time between setup of the line and invoice creation. Thus it might be that you have to pay for up to two months (one in advance and up to one month between line activation and invoice creation) as base fees.
And thirdly: Sole contractual language is German - thus also service is given in German language and any support in a different language is only given on a best-effort base - which may also include that there is no support in other than the contractual language at all.
