Airbnb offered great support through this whole issue and I was able to move to another place BUG FREE & within the same price range.
I have rented properties of different budgets through AIRbnb for many years in different countries and I have never had to checkout early of an ongoing reservation nor had any difficulty dealing with any Hosts.
I always focus on commenting only positive experiences but this time I feel is important to register this distressful event because the host altered actual reservation dates and I found their reply messages odd and offensive.

Good location in a quiet neighborhood very close to a park and about 15 minute walk to Plaza Hidalgo, the heart of Coyoacan.
Cute apartment but too rustic for me. The issues I countered were:
1-There were garden bugs inside the house. I found large slimy worms in the kitchen floor specially at night. In the morning when we were having coffee we saw small creatures running on the dining table. They looked like little roaches.
2-Plumbing/ water issues
EXTREMELY LOUD noise heard through the whole house when you use Hot water in the upstairs shower. Hot water takes a while to come out specially in the shower. There was not enough hot water for two people to shower one right after the other, you have to wait. Difficult to regulate the temperature for me it was either too cold or too hot.
Kitchen has no hot water to wash the dishes and during this time in Mexico city the water is pretty cold so very uncomfortable to wash the dishes besides the faucet shooting water in different directions so my clothe would get all wet too.
3-Headboard is not well adjusted so every time I moved during the night it would hit the wall and wake me up.
4-My first night a cute little cat spend a long time meowing by the door. It made it difficult to fall a sleep.
There was not only one major problem but many little issues and some of them were my fault for not reading well the description of the place.
Like:
4-The bedroom has a small area where the bunkbeds are so I would not call it a second bedroom is more an extension of the main bedroom. Obviously you have to go through main bedroom to use bathroom. No Privacy
5-Share entrance. The apartment is in the back of main house. For me it was a privacy issue and felt I had to keep curtains closed, which made the ground floor darker and colder than what already is. Also my second night Santiago came in Knocking loudly with keys on the glass door, it was completely dark because there is NO night lighting outside. I thought something really wrong happened, I was afraid to open the door as I could not see who was knocking. Apparently We had locked the street entrance and the other people who live in the room right outside could not come in. So I was reminded I had to leave it unlocked. Stupid issue but not pleasant how it was brought to my attention.
6- Steep stairs and no TV were a problem for my mother but again that is stated in their description which I did not read in detailed. I honestly jut went by the good reviews of previous guests.
I was NOT COMFORTABLE in the apartment so I respectfully stated my complaints to the host & requested an early check out the second day of my stayed. I gave a 2 day notice and I was aware of AIRbnb cancellation policy of loosing 50% of used nights.
THE HOST DECLINED my request of early check out.
I am a calm & respectful person specially when I addressed other people but I personally found the host reply odd, rude and offensive. They suggested to go to a 5 start hotel if I wanted to be more comfortable and pampered. And to go for a walk and have a glass of wine then I would feel better. They describe what they use the money of the rental for so I should reconsider checking out early or requesting a refund.  I contacted Airbnb who contacted the host. Later on the Host told me they would only refund 25% of unused nights which at this point I didn’t care. I would have left even with no refund.
So finally they accepted the request to leave early but then I realize THE HOST ALTERED my check out date. Registering my staying as a whole week instead of 3 days. Again at this point I didn’t care about the money I just did not want to record FALSE INFORMATION on airbnb site.
I contacted Airbnb again and thankfully they were able to registered my actual checkout date.