In many cases two attorneys well versed in real estate agency law will differ on opinions as to the same set of circumstances; further minor differences in circumstances will result in different decisions.  

My question - Is it possible to just put a dual mail box in place of the single mail box?

For larger amounts, you could contact a collections agency.

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That could include court and/or collections agencies.

Open to any agencies and willing to pay heat as part of the deal. 

However, in most cases collecting on the personal guarantee is difficult if not impossible.Since Dodd Frank and the CFPB, judges have punished holders of paper where the note was originated in some way that violated this act and the agency regulation by allowing the note to remain in force but severing the security interest from the note.

Thanks, I find it confusing between all the reporting agencies and the different scoring models.

In many states, a disputed earnest money deposit on a contract involving realtors normally gets transferred to the Dept of State or whatever agency oversees real estate licensing. 

If he puts something on the MLS then he will have an agency relationship with the seller.