As long as you have your money order receipts you should have a case.
There is a problem.
Money orders can generally be cashed by anyone.
Any time you pay anyone for something such as your housing rent, you
need to make very sure you receive a receipt immediately.
For example, writing a CHECK the guy would have to sign it in order to
cash it or at the very least go into his direct deposit and there would be
record of it being deposited/cashed.
If you handed your landlord a money order, he should have handed you
a receipt immediately.
Never ever just hand someone a money order without receiving a hand
written receipt in exchange.