NH Danube City in Vienna

I chose this hotel for its proximity to the convention center and stayed for five nights. On the fourth day, I woke up to find some bloodstains (not mine) on the bedsheet under the pillow. I removed the sheet and placed it on the floor. When I returned in the afternoon, I was appalled to discover they had put the dirty sheet back on the bed, simply rotated 90 degrees. The bloodstains were still clearly visible. I went to the front desk, but their attitude was unhelpful. I then asked for the manager, who also displayed a poor attitude. Despite this, they eventually agreed to immediately change the bedsheet, duvet cover, and pillowcases. After they changed it, it dawned on me that the bedding I had on my first night might have been used by one or even two previous guests. The photos I took clearly show creases on the newly replaced sheet, indicating it had been folded. In stark contrast, when I first checked in, the bedsheet, duvet cover, and pillowcases were completely crease-free. I only slept on the left side of the bed; the right side remained untouched.