Simone, there are many half-truths you are listing, for example the fact that you insisted on somebody welcoming you in my appartment. That wasn't possible but there were alternatives to get the key (besides, it would have been a detour of 10, not 30 mins). It is a common practice of to deposit the keys at a place close to the accommodation.
It might be true that I wasn't reachable per phone since I spend the summer abroad. Nevertheless my co-host did the best possible job and responded within minutes.
At the end of the day I think that we are both quite emotional about this happening, but I would ask you to reflect about your way of communication and your unilateral point of view. Probably we both made mistakes, but your assessment is definitly not fair.