While we can't advise you on your rights in requesting Pet Owners for cleaning compensation, what we can suggest is you could try messaging the Pet Owner a link to our Paypal Account https://www.paypal.me/petcloud through your PetCloud inbox and say "Hi Name, I had to go through a fair amount of cleaning of my lounge and washing after [Puppy Name 1] and [Puppy Name 2] as they weren't fully toilet trained, would you possibly be able to pay an additional surcharge of $50 which I feel is reasonable to cover my costs?" and then we can fwd the payment through to your account.
We would also suggest taking photos using your smart phone and uploading them through PetCloud.
It's tricky, because sometimes because even if a dog IS toilet trained, they are staying in an unfamiliar home with unfamiliar smells and it can take more than a short stay for dogs to understand they right place to toilet. It's also important to update the Pet Owner daily throughout the stay about what their pet is up to, including whether they are toileting in the wrong spots (and you can't supervise a pet 24/7 as you have to sleep, eat, shower sometime too!)
Perhaps on your listing description (for future bookings) write "A cleaning surcharge is payable of $50 if your pet is not toilet trained." If you didn't have any cleaning charges listed in your description before the booking, it may be a little difficult to then tell the Pet Owner that there is a charge (doing this is called "Bill Shock" and is not likely to get a positive reaction from them). Maybe you could put it down to a learning experience this time around and then Puppy-Proofing your home for future guests? https://www.puppyleaks.com/dog-proof-your-furniture/
WATCH: How to remove Stubborn Pet Stains from Carpet (if you've already tried Baking Soda and Vinegar)
In general, however, try to avoid ammonia based products. Stick to baking soda, vinegar, and an enzyme based spray that neutralises odour - as using an ammonia based product will make pets think there is another dog or cat marking their territory and will encourage your pet to repeat the same behaviour!