After a few more calls with the owner of the appartment where we came to no solution, we checked with hotels.com through whom we booked and paid the deal. Good thing we did so, because they agreed this is not acceptable and booked us on a better hotel at no extra cost.
Meanwhile I checked the ratings on the guesthouse we originally booked and saw they've gone down significantly since we booked. From like 9.0 to 6.0 where the last ones were around 4.0 (all out of 10.0).