Verbal agreement and Written agreement are totally different. One is more important than the other. First of all verbal agreement nothing is guaranteed. Verbal is all talk, and most of the time it is just discussion on what ideas they have and basically it is a discussion on what they will do. In my opinion nothing should be done until it is set in stone. All work and agreements should be written documentation.To make sure all work is followed by legal documentation if there is any disagreements.