One month she paid late so her balance due is $840.

She was running more than two weeks late the following month, and I'd added the appropriate late fees, making her balance $1,171... and then I got a text saying she'd made a payment... of $17,111.Obviously, that bounced. 

It's NOT water proof, and it requires vapor under-layment AND padding, the other was integral and had all that.

As of right now, my contractor is going to install a vapor area and call it a day after making the repairs.

Chances are there is no vapor barrier on the exterior side preventing moisture from penetration the block.

You'll also have to seal the existing concrete with some sort of vapor barrier.Easier to just go the concrete route....  

Yeah, it Has to have a vapor barrier behind it, even when installed correctly......crazy that someone would put it up without it.

She only paid $180 of her balance and nothing else that week. 

Another misconception is that vapor simply vanishes into thin air without leaving a residue.  

Even with a generous grace period, although the tenant is current on rent, there are late fees from 3 months' rent on her balance.