Marketing specialist that can help me with making a flyer

I need someone who can write and design a post card/ flyer that I can mass email to prospects. Have been primarily working as a professional salesman past 1/2 century, concentrating first half in institutional furniture, last half in office furniture selling ergonomic products I invented in mid 90's, have 2 utility patents and 1/2 dz design patents. 20 some years ago I created a domain name called "calltheplumber" and having been retired last two years have found I needed to develop this name and in doing so would License the name and logo (trademarked) to plumbers starting in SC, but first step is contacting them via 6"X 9" postcard depicting on one side our prime mission, to get customers to click, call or text them. I listed several ways we do it, using our website, toll free number direct to them, CTP email, full vehicle wraps and our extensive use of internet and ground coverage exclusive territory to do it in. I sent this to 295 licensed plumbers 10 days ago and received not one call. I wrote the postcard I sent to these plumbers writing it in such a way, that it cut out a lot of BS and by referencing the old way Plumbers advertised (YP) it gave them an idea of pricing and should have got the wheels turning to how easy life could get without the hassle of that pesky chore of needing customers to stay in business. I did try Upwork and enlisted the services of two different direct response copywriters but none ever got started and I lost 2 weeks. I want to do a 3000 plumber mailing covering NC asap. so if my post card is bad I hope one of you expert writers can make it just about memorizing to the point they can't put postcard down until they dialed my number on the back or anywhere in between. Without Licensing plumbers I have no plumbers, this card if effective will allow me to get in front of them and persuade them to become CPT plumbers.