I'm Ava from Shopify, I'd like to help here.
I can understand the frustration if your mobile cart is seeing some issues, especially if it's affected sales! Can I ask if this issue is still ongoing? A few days have passed since you've posted here, I wanted to check if a resolution has been reached yet.
An issue where the products are not loading in the cart sounds like it may be theme-related, as your theme would control how products are displayed on the live store. If this is still ongoing, it may be best to reach out to the developers who created your theme for assistance. The Testament theme was created by We Are Underground, you can reach out to them for help by clicking here.
Let me know how you get on!
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