Unable to Retrieve Records or Fetch records Based on Modifiedon Value

Hi,

 i have to fetch records from custom entity like "Test" based on "modifiedon" date field from Contact entity

there is no relationship between two entities , i get modifiedon from "contact" entity and pass this value to "Test" entity , in test entity i have a custom field called "FromDate" , i couldn't retrieve data from test entity by passing modifiedon value to fromdate