We had lost rent due to non payment by the tenant. How do we report those loses?

You don't report them as losses but you don't have to report them as income.

How do I post this loss. Your answer indicated that I do not have to report them as income but I get W-9s because when I rent my vacation home through another business not my own

It is physically impossible to lose, that which you never had possession of in the first place. You only report the rental income that you "ACTUALLY RECEIVED" in the tax year, and that's it. So you don't have a loss of anything, any way you look at it. You just don't have the income that was expected.

You get W-9s? You mean 1099-MISC?

As the others noted, all you have is a loss of opportunity, and that's not a loss you can deduct.