and Illinois law prohibits me from representing any customer as a result of contact in this forum. If you need representation
, you will have to hire local legal counsel. That said, you can send your own letter, though to be frank, it probably will "fall on deaf ears." You've explained yourself well in this forum. I suggest that you send a letter reciting the facts and summarize that you do not understand why the prospective landlord would cash a check for a property where possession could not be granted on the agreed-to date of July 1, and that the failure to deliver a lease agreement, demonstrated to you that there apparently was never any intent to lease the property to you.
Then you finish up with something like, "I would like to avoid resort to legal action in resolving this matter. However, if I do not receive a return of my security deposit by no later than ??/??/???? [10 days is sufficient, in my opinion], then I will take appropriate legal action to enforce my rights."
You can't threaten to go to the police unless he returns your money. That could be construed as criminal extortion
on your part. Then, you wait out the time period and if you don't get your money back, you start making waves.
Hope this helps.