You should also consider all of your in-app purchases, as well as for your app. You said that your in-app purchase status is ready to ship. Thus, you just need to click on this button in your in-app purchase position. Your in-app purchases are also forwarded to Apple and it will be approved along with your In-app purchase.
They declined because all of your in-app purchases are ready to ship. You can send it by uploading a screenshot to your in-app purchases.
I hope for this help.
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