I have submitted an app to shopify for review and my app has got rejected. They says, "Apps that bypass Shopify Checkout are not accepted on the Shopify App Store. Payments and orders cannot be processed outside the Shopify platform."
I have implemented it both on product and cart page. When click on "Pay with chloe", a popup opens asking for all details. When submit the details on the popup, an order is created on shopify with payment as pending and customer receives message/call/email for completing the payment via selected channel. When payment is done by customer, order is marked as paid.