When you create a new Shopify store. The store comes with Shopify default shipping rates. These values can be higher than what you are paying Mayzing for shipping. And while this means you are making profit on your shipping, it can impact conversion rate as customers find the shipping too expensive.
Go to your Shopify dashboard, and find the "Shipping and Delivery" section.
Click on the arrow next to "General Shipping Rates".
Scroll down and edit the shipping rates for each of your shipping zones to the value you want them to be.
Make sure you are happy with the rate for each zone. And at the top of the screen, press "save changes"
Your new shipping rates will now be active in your store.