Tenant has blocked our numbers....next move?

[Nancy P.]

Couple moved into our very small condo (550 sf but nicely finished and nice area.)  Male had a felony which he explained and we decided to allow in.  They promptly broke up---far too small when one is working at home.  She had the better job but he had the felony so she moved out with our permission.  She moved out mid February, rent was paid for the month.  March 1 the nonsense begins.  "Can you cut the rent in half since half the people are gone?"   No. Worked out a payment plan, pay for four weeks, he signed the agreement.  Paid for two weeks.  In the meantime his car is leaking oil and the association gave him two weeks to fix it.  Now he's blocked all of our numbers.  Illinois will allow evictions again on April 3, but I'm sure it will be a mile long line to begin evictions.  I need to serve him notice but wondering what the best way to go about it is?  We already offered him an out on March 5--move out this weekend and we will give you the full deposit if no damages...he didn't accept that offer.  I REALLY don't want to go through eviction as I truly believe it will be months.  What else would you suggest?  I could get his car towed but not sure how that helps except maybe using the threat as leverage.