We are glad to respond to a formal RFP. A few things make our response materially better, and they are usually the things that get left out.
Tell us the commercial outcome you are measuring, not only the deliverables you expect. Tell us what has already been tried and what happened. Tell us who has to approve the work internally, and what your timing is driven by. If there is a budget range, say so; it changes what we would recommend rather than whether we respond.
If you would rather talk it through before writing anything down, that is usually faster for both of us.