If the wrong shipping method has been assigned this can be down to 1 of 2 reasons.
1.) The order does not fit the expected shipping methods shipping rules.
2.) The shipping method fits 2 or more shipping rules.
To find out which of the above issues has arisen run your order through the shipping rule tester. You can get to the shipping rule tester by navigating to Settings > Shipping configuration > Shipping rules > Shipping rules tester or by following this link: https://my.storefeeder.com/Settings/Shipping/ShippingRuleTester.aspx.
Once you're in this screen I recommend clicking into your settings in the top right and setting up your options like this:
You should be able to see how many shipping rules and which shipping rules the order matches along with the "Specificity" and which ones don't.
StoreFeeder will apply the most specific option to an order. Once you have tweaked your shipping rules to your liking you may hit the "Re-apply Rules to Order" button. If you click a shipping rule you can see a more detailed list of which criteria matches and which does not.
What if my orders aren't getting a shipping method automatically assigned to them?
The above steps apply to this as well, the cause of this issue is likely down to having no shipping rules that match the criteria of the order.
How do I setup and edit my shipping rules?
If you need assistance setting up shipping rules you can find our guide here: How to create Shipping Rules this guide also covers how to manage and edit your shipping rules.