Also, how do so many wholesalers get away with it without being punished if this were illegal?

Don't waste the time, just serve the 60 day notice and if they are still there after 61 days, have an attorney file an unlawful detainer suit against the tenant.

The 2nd issue is rents or monies pass due, if she signed it and did not pay it, then she is in breach of her lease.Personally I would move unalaterlly, file for unlawful detainer for the monies owed with late fees, and deal with her case, maybe see if the attorney can open a counter lawsuit for that case to try and force her to folder her cards. 

Be very careful of bad faith tenants and "unlawful ouster" that arises in 504B.365 Subd. 5, 504B.231, and penalties in 504B.225 which include "reasonable attorney fees." 

As a courtesy, you can consider writing him a letter informing him that beginning next month you will be enforcing your lease and spell out the section that specifics what his obligations are and I suggest that you start communicating with him via electronic mail from here on in.Prepare to file a notice to pay rent or quit as soon as it applies and proceed with an unlawful detainer.

Basically, you get punished by the credit bureaus, if you make a payment on an old debt. 

To me, it punishes tenants who's hardly at home.

Am I punishing this seller for running his business smoothly? 

And the common denominator here and for your problems in Detroit is..... tenant selection by.... a PM.Why do you keep punishing yourself? 

Women get "punished" for not being "nice" in ways that men never do.Think about this if you have a daughter.