When a prospect has gone silent, one possible call-to-action is to ask for a 5mns debrief call.
Just to understand why they went silent.
If positioned as:
- a quid pro quo (considering time/efforts put into getting on a call with the prospect, doing a demo, etc..)
- non-threatening (understanding, not selling)
it can be a good way to get a prospect resurface & to open up.