{"success":false,"error":"Invalid request","version":"V7.5 PAYMENT FIRST - Create Order AFTER Payment Detected","database":"Centralized Database.php","logic":"NEW: Payment verification \u2192 Order creation (not reverse)","features":{"payment_first":true,"auto_order_creation":true,"multi_user":true,"auto_sync_from_db_only":true,"signature_authentication":true,"centralized_apps_script":true,"individual_sheets":true,"flexible_order_code_matching":true},"flow":{"1":"Client sends: order_code + amount + user_id + customer_data","2":"System checks: Bank API for matching transaction","3":"If payment found: Create order in database automatically","4":"If payment not found: Return paid=false, keep checking"},"help":{"get_bank_info":"GET gateway.php?action=get_bank_info&user_id=YOUR_USER_ID","create_order_manual":"POST gateway.php with order data including user_id field (fallback)","check_bank":"POST gateway.php?action=check_bank with JSON: {order_code, amount, user_id, customer_name, phone_number, address, products, notes, facebook_id}"}}