I'm not on site, the plumber, ordered by my PM, claimed nothing

I'm not on site, the plumber, ordered by my PM, claimed nothing wrong with the hot water

the Indian, my tenant (short term for my vacation home) called my PM (property manager) for no hot water, the PM ordered the professional plumber to fix. The plumber went there and back claiming nothing wrong with the hot water. Then PM charged me for the trip fee for the professional plumber even though no jobs done. Then the tenant (the Indians) cancelled their credit card payments claiming no hot water.

I believe I have strong evidence, but the question is how to protect my money? please give your advice.