Ugh, what a jerk. I just can't understand some people. Thank you for taking those two dogs on, though I know it's frustrating to have house breaking issues.
You ought to consider getting 2 separate small crates that's only big enough for them to turn around in. When I first had Stella, I kept her in a larger pen, which she started peeing in. When I moved her into something smaller, she hasn't had a problem. When they're in smaller area, they won't be as apt to soil it!
Also, it's important to get them on a set schedule. Don't deviate from this schedule at all for the first several weeks (or longer). The consistency really helps them learn.
When bringing them out, I'd go out with them and watch. If they don't go, bring them back to their crate, and try again every half hour until they do. When they come inside, do NOT let them out of your site. Someone once gave me the awesome suggestion to hook the dog's leash to your belt so they can't sneak off. If you catch them in the act, say "No!" and bring them outside. If they potty outside, praise them like there's no tomorrow.
Some Chis are harder to train than others (mine has an absolute nightmare to house train), but be patient and consistent. It will pay off. Good luck!
And by the way, welcome to the forum!