This happened to me once. Lesson learned. I require 1/2 upfront & signed estimate (doubles as contract) BEFORE design is even considered. Payment is due in full PRIOR to sending. This doesn’t necessarily save my butt if the client bails…but at least I’m making my materials cost from the first payment. I find it also necessary to state that all work is under the sole copyright of my company. I have found people like to look, steal, and do it themselves. Not good when a gal’s trying to make a living. Hope this helps.