I can't remember what the reasoning for why all of a sudden they wouldn't be happy with the arrangement.

I have read my first few books which has wet my appetite, and arranged 2 beginner seminars in the next couple of weeks. 

I would rather make an arrangement with the debtor.

I hired someone, who was able to handle all the communications with the IRS agent, who kept me in the loop on a regular basis, and was able to package up my crazy complicated tax documents into a professional looking arrangement that "blew the socks off" the IRS agent.

As to preferential treatment, they may have special arrangements with the owners.

A few years ago I garnished the wages of a pre-school teacher. 

In the United States, when credits are applied to a purchase price the agreement becomes a financing contract and these contracts have been identified as predatory lending arrangements under the Dodd-Frank Act.

You make arrangements with the seller for them to be the bank for you.  

OTOH, if you and the tenant knew this would no longer work and had a different arrangement in place and the tenant tried to deposit it anyway, maybe not. 

Suggest you inform him that he is expected to move out and it was a business arrangement.