There aren't many things that "appear" to be leaks, they usually are leaks and if it's been leaking since May you are going to have way more issues to worry about than a premium plumber charge.

most PMs charge a month's rent to place a tenant. 

Like I brokered a 22  lot development of duplex's for a builder and just charged him 30k flat fee per sale.. they sold for 225k each back in 05 when I did this and I sold them all in one weekend at a big event i paid for in San Jose CA.. all to CA investors it was my fly and buy program I did in those days..

You can always charge an air and surface scrubbing fee from their security deposit after they've moved out. 

Start dates, who's in charge of what task, price, status bars, completion dates, etc. 

bottom line  BAD ACTOR GUILTY as charged is my thoughts. 

On the other hand, you stated that the management firm was charging 15% and had a 15k expense. 

I own a unique mobile home park in South Carolina that's relatively small (5 acres) comprised of 12 lots (I own 8 of the homes while the other 4 are owner-occupied and charged lot rent) along with a house (3 units). 

We even allow pets but charge $50.

I've also talked to a couple of experienced investors on the phone and I will be forever grateful to their advice and for helping me out without charging me thousands of dollars for a coaching program.