Since I know how the World of Realtors works, I think this would be a huge waste of time.
The OP client has never actually used the site for anything and potential Real Estate Clients, when blindly searching for property, are not going to be searching for this Client's NAME.
you may as well suggest Google-Bombing the deadbeat Client's name to end up at [en.wiktionary.org...]
Also- I don't understand this issue about who owns the domain.
If the OP registered the domain, paid for it, and built the site, but never received any compensation, he is somehow obligated to GIVE the domain to the deadbeat Client?
It would appear that every intention was there to transfer the site ownership and content to the Client once it was paid for.
But the Client decided to stiff him.
This Realtor Client just walked away from this deal.
If the OP wants to get paid (which is what this is thread is supposed to be about) he needs to use every possible legal recourse available. And that does not limit methods to "the legal system".
I still think the "Site suspended due to non-payment" is an excellent incentive.
Their name is not up their, nor any reference to them.
No one else sees it except the deadbeat Realtor and hopefully the idea that there is "a page on the Internet" as an eternal reminder that she is a deadbeat will get her to cough up the balance due.
Right now she feels no obligation or guilt. She walked away and there were no consequences for her actions.
and if that does not work, a few months of the debt being listed on her credit report might also work
(but make sure she is aware that it has been reported or it won't work).