Oh dear @Helen427
I am sorry you had an upsetting experience with your first guests. But your response to their review makes it stand out so much more, and will unfortunately put some guests off from staying with you.
It has quite a few spelling/grammar mistakes, is unecessarily long, some matters (such as whether they live in NZ or not) are irrelevant and quite a few of things you complain about are down to your lack of experience as a host (I do accept your guests behaved badly).
For example, it looks strange complaining about two people staying in a room for one, when you were the one who accepted the booking.
As an experienced host I hope you don't mind if I give you a few pointers.
1. You should never have accepted two people for a two week stay in a room clearly only fit for one.
2. I am not sure why Airbnb didn't tell you when you called them but it is incredibly easy to amend a booking from one to two, you just go into the booking confirmation, hit the amend button and change it from one to two.
3. You shouldn't have let the guest check in before paying for the second guest
4. As a host you need to manage your guests. You should have made it clear that their belongings needed to fit in their bedroom not be left around the house and damp towels kept in the bathroom.
5. You should have made expectations clear around cleanliness in the kitchen and clearing up after themselves and asked them to leave if they continued to break your house rules.
I am sure you will learn from this and hope that going forward you get much nicer guests.