Renters leaving early & skipping last month rent - Cook County IL

[Sean Graham]

I have tenants who notified me on 7/1/18 that they are leaving on 7/31/18 even though their lease expires on 8/31/18. They have not paid me July rent and they are not going to pay me August rent. Their security deposit is less than their current month. There also may be damages to the unit in which case I will need the security deposit. 

The unit is in the suburbs of Chicago. What options do I have in pursuing payment from them? Has anyone experienced this in Cook County, Illinois? Does anyone recommend an attorney to use? Should I have a creditor go after payment?

I know there are ways to avoid this in the future, but I'm hoping to find a solution for the current situation. 

Thanks in advance.