Courtyard by Marriott Munich Garching

I have booked a room for 3 adults, while on the arrival I have realized that the room is too small for even 2 people. when I asked if the room can be upgraded - I was told that the hotel is overbooked and there are no bigger rooms available. I told the staff that I'm Marriott Elite Gold member and would appreciate if the hotel would find any chance to get us bigger room during our stay from June 29 through July 6. I was checking every day since then while without any success. It appears that as long as i booked the hotel via Hotels.com (not directly via marriott) I'm no longer treated as Marriott Elite Gold. It was extremely hot in Munich during our stay and the AC system in my room was not working I was told that it is hot outside (28-29C) and the HVAC can't cope with the heat, while the temperature in the corridor was OK. Chip and poor quality towels in the bathroom, size too small and just two per person. No slippers for guests. The shower gel and shampoo provided in extremely small tubes and quantities. I had to request to refresh the shower consumables several times as it was just not enough. The Shower compartment had no door/curtain so once any of us would take a shower the entire bathroom was flooded. We didn't feel as guest in this hotel. The front desk personnel not friendly at all. No wish to make your stay comfortable. I wonder if other marriott hotels in Munich are treating guest in the same way. At least my family and I are extremely disappointed.