Terminating lease before tenant moves in

[Andrey V.]

Hello. I am looking for a legal advice.  I own a multi unit property (North side of Chicago). My new tenant is scheduled to move in on November 1st.  They have a signed lease from me which, unfortunately, I emailed them way too early..  We had an agreement they will pay security deposit and pre-pay 2 first months of rent upon lease signing because they fall into riskier tenant category. I received a security deposit and a half of first month rent and they said the other half is on its way.  I sent them the lease.  I never received the other half.  My other mistake was I never specified these terms explicitly in the lease.  It was agreed upon over emails.  A few days ago, they emailed me stating the balance will be paid with cash when they get the keys.  I do not accept cash and those are not the terms that were agreed upon.  So, I am trying to figure out my options before they move in. My preference would be to terminate the lease and refund whatever I received from them and move on.  Do I have sufficient reasons to terminate the lease?  Do I have a sufficient reasons to keep their security deposit if lease is terminated since I have been waiting for over a month for their balance to be paid?  In the worst case, if I can't terminate the lease immediately, can I refuse them keys and/or terminate the lease on the spot if I don't get the full payment on or before the move-in date?  Thank you.