BUt why cant i get a lien when the person clearly agreed to pay back in a contract and he failed to pay? 

Personally I would sell and take your losses and look to invest elsewhere.

I assist clients in figuring out methods to finance real estate, and house hacking is my bread and butter.Something i've done personally and continue to help new inspiring investors do every day.

I believe Airbnb has a system in place for handling disputes between guests and hosts, and they may offer compensation for damages or issues caused by a guest.I would start by documenting everything: A detailed written description of the incident and timeline, records of all your communications with the guests, before/after photos of the damage done to the furniture and the bedsheet, a statement from the neighbors about the trespassing incident, etc.Then I'd approach Airbnb looking for guidance.

That said, that isn't the kind of action I'm personally cool taking part in or giving advice to others to do. 

You will ultimatley come away with better opportunities than the scattered approach you've been relying on.

Personally, I have a boutique investment company.

House hacking will also give you some personal "property management" experience.

We have a person on board with a degree in design, so we usually tweak the floor plans for sight lines and function.

Guiding, advising, meeting in person, hours on the phone, discounting on property price and services.Properties appraised for more than you paid, you sold for more than you paid.