thhe guest does not leave: it is the second night he spent with a friend in my flat without paying.

[Ramon7]

THe guest told me that his credit card is "out of credit" hence he has to wait until the 5th to process the payment. however, he also asked to extend his stay (with a non decleared guest) in my flat for 8 more days (from june 29th till july 5th). What shall I do?

[Anita-and-Fredrik0]

Get in touch with the airbnb helpcenter asap! He should have paid in advance and the money recieved by you on the first day of the stay. 

Airbnb will likely call the guests and sort it out. I would not extend the stay, and I would discuss with airbnb what will happen in regards to this guest writing a review. 

[David126]

Time for them to leave.

[Andrea9]

@Ramon7 @Anita-and-Fredrik0

This sounds like a scam.

The whole intention of this booking service is so that situations like your's DON'T happen.

A guest has 24h to make payment to Airbnb. If that doesn't work, the guest does not have the reservation, and anybody staying in your place will first of all in no way be covered by Airbnb, and  will probably sneak out at some point without payment. And now they are even adding an additional person!

Did any of this even go through the messaging system?

Do you even have a record of this 'reservation' in your reservation list?

I suggest you contact Airbnb contact link asap!

If there is a confirmed reservation (probably not), then you are covered. 

But I would then definitely add the extra expenses for the second person.

If there is no reservation, I'd call the police and report the guest for scamming you.

[Ramon7]

Thanks for this answer. In fact one of the two booked the flat until June 29th. They asked for an extention, claiming that the payment for this extention could not be processed. 

I am afraid it is a scam. The problem is that I am in Geneva and the flat is in Milano.