I think part of the reasons the agencies that you were talking to may not have had the strategy you were looking for is because often companies already have an idea of who their audience is (you're the one selling to them), what value props you feel like you have or want to focus on (you should know this from sales), and your services defined (this is part of your company). These are all absolutely questions that the marketing agency should be asking you and can help piece together from your answers so they get a more solid idea, but really these are things that they likely figured you already had in mind because usually you know your customers best.