Shopify Payment Gateway Setup

I have a monthly rental platform in Shopify, where the user can access our products for a predetermined monthly price. Currently I am having difficulty at the Checkout stage. I have activated all Shopify payments settings and registered with Razorpay but still my store isn't accepting payments... (Budget: ₹600 - ₹1500 INR, Jobs: API Integration, HTML, Payment Gateway Integration, Payment Processing, PHP, Shopify Development, Technical Support, Website Design)