If you do not pay child support the State of Florida, through the Department of Revenue, can suspend your license. If you are having a hard time keeping up with your child support because your income has gone down or you lost your job, the first thing you should do is modify your child support, either through the family court system or through the department of revenue. Also, pay what you can but as time passes the department of revenue may intercede and direct the State of Florida to suspend your license.
Ultimately, you never want to disregard any letters from the department of revenue and you need to be proactive in order to protect your license. Finally, speaking to a family law attorney may help to give you insight into the Department of Revenue.