First of all we would like to tell you that this review caught us really surprised! Yes, we admit that it was the wrong apartment at first, but in a few minutes we solved the question, which I believe that this is the most important thing when we rent an apartment - the host take care of us and bring solutions. By that time, we had no idea that this was so bad for you because the feedback we had was good!
During all your stay, we had not received one message - neither or airbnb/mobile/ (Hidden by Airbnb) (we are available through all the platforms) - regarding the problems you had... And that is what brings us to a really hard and unfair position, because we would like to help you with everything and we couldn't because we didn't know of anything you just described.
The wifi in the apartments work really well, as we have improved it to the fastest internet in Porto a month ago, so I am not sure what happened with this topic too!
Regarding the stairs, you can see on the listing that we don't have an elevator and that is only stairs (as it is in most buildings in Porto).
We have bought the mattresses in the best shop here and they are top confort - we really can't put everyone happy - but we try :)
We have never had complaints about noise in this apartment, as it is on the 3rd floor, so maybe you caught a busy night here in Porto.
To finish, apartments on airbnb exist to give an authentic experience to the guest, we try to pass all the info and tips that don't appear on the touristic websites and books... And I believe this is the main reason for choosing our place to stay. People who are looking for an extra luxury touristic experience are made for hotels, just that!
Thank you for your feedback, we really appreciate what guests can tell us about the stay so we can improve for the next one! Wish you the best