You can delete any prospect accepted on your account, no matter how many messages he received or is about to receive. However, before you delete the prospect you need to know some things:
The deleted prospect can't be brought back (unless you import his data or add it manually).
Once you delete the prospect, you'll be able to generate or import them once again when adding prospects to some campaign (unless you blacklist them).
Once you generate/import the prospect after deleting them, the history of communication and action towards this prospects will be removed.
NOTE: If you want to get rid of the prospect (don't send any more messages to them) we recommend unqualifying instead of deleting - this way you make sure, that the prospect won't be generated once more. You can also create a separate campaign for these prospects and transfer them there, in order to remove them from the other campaigns.
How to delete prospects?
In order to delete a prospect:
Go to the campaign from which you want to delete them, or go to My contacts tab to search among all campaigns.
Choose the prospect or select a bulk of them.
Unfold the Actions menu and select Delete:
That's it! Now your prospect is deleted. Now, make sure not to contact them again by blacklisting!