WooCommerce API & Checkout Fix

I need help untangling two urgent WooCommerce issues on my live store. First, the external API feed that pushes product data into WooCommerce is no longer lining up with what shoppers see on-site. Prices and stock levels sometimes arrive correctly, then drift out of sync a few hours later... (Budget: $30 - $250 USD, Jobs: API, API Development, API Integration, JavaScript, PHP, REST API, WooCommerce, WordPress)