Hello Jackson,
I'm sorry to hear about your situation. As a property manager it's always disheartening to hear these kinds of things, because most people will then assume we are all this bad. My advice to you would be to use this experience to create a checklist of what to seek from the next Company you choose to handle your investments. You can never ask too many questions when asking someone to handle one of the largest investments you will ever make. A lot of the items you mentioned I feel would have been caught before signing up with the proper screening. A great place to start when looking for management companies, as previously suggested, is www.narpm.org Being a member doesn't guarantee that they won't be bad, but Companies who invest the time in being involved in the organization and becoming educated seems operate at a higher level (my opinion of course). Our membership has proved to be invaluable for our business.
Reach out if you have any questions as you move forward, and keep you head up.