Shop Foodocracy review for ShipStation

Our new 3PL uses this app for shipping labels so unfortunately we are stuck with them at least for now. Since moving to them I've seen a 20% increase in my shipping costs. They use Stamps.com for USPS which has shitty rates and you can't switch to shippo or pirate ship. You can hook up your own accounts if you have them for UPS, Fed Ex, DHL and some others but none that handle USPS. I'm also not in love with the way the app works and the customer service is non-existent. I want to add a rule for the packers to add an insert for orders auto-tagged in shopify as first time buyers but I can't get it to work and I can't get anyone to help. i'm spending way too much of my time on this app.