The Company That Laid Me Off 3 Weeks Ago Is Withholding Severance Pay If I Take A New Job There

I was laid off three weeks ago and signed a separation contract with the company that includes severance pay. Now I have been offered an interim job with the company that may turn into a permanent job and HR stated, "If the interim role concludes without placement into a permanent position, your separation pay will resume." Do I have a cause of action if they withhold my severance pay indefinitely after taking the job and staying there permanently?

For context: the separation agreement makes no reference to forfeiting severance pay after accepting a new job at the company. The offer letter I received does not mention losing severance pay, either. For reference: I live in Florida, the company is based in Illinois and I worked remotely.