Hi @Lisa847
All the ways of contacting Airbnb are outlined in the CONTACT AIRBNB post in the Help Forum - about third post down - have a look and you can give Airbnb a call.
I would also recommend you read the Airbnb Help Centre and community guides in this forum, as the issues you queried here are explained in their Q&As.
If you say in your house rules that only guests with verified ID and a clear photo can book and you have ticked this option under Instant Book, then you won't be penalised if you cancel a guest who doesn't provide this as they haven't met your house rules and shouldn't have been able to book in the first place.. If you don't have IB turned on (and I wouldn't recommend you despite how Airbnb pressurises you do this - then you can decline.
If the guest can't work out how to upload photo ID and a photo of themselves, they can call Airbnb to talk them through but it's normally fairly easy for most young people who are tech savvy.
With your prior guest if she cancelled because you had a dog and this was clearly outlined in your listing at the time and you had ticked the box on the listing to say you had a pet - Airbnb had no reason to penalise you.
The guest should have been refunded in line with your cancellation policy. The only way this wouldn't have happened is if you voluntary chose to give the guest a higher refund than they were entitlted to.
Give them a call now to try and resolve these issues.