Shopify Checkout & Theme Fixes

My clothing store runs on Shopify and I need an expert who can jump in right away and get the checkout working flawlessly. The highest-priority item is payment gateway integration: some customers are reporting failed or stalled payments and I want that resolved first.

Once the checkout is humming, I’d like you to:
• Integrate an automatic shipping solution so real-time rates show at checkout and printable labels are generated inside Shopify (apps like ShipStation or similar are fine).
• Bring the theme up to date, cleaning any Liquid, CSS or JavaScript conflicts introduced by the latest Shopify core changes.
• Hunt down and fix bugs or console errors site-wide, then test thoroughly on desktop and mobile so every page scores well on speed and responsiveness.

I’m aiming to move fast (ASAP), so please tell me:
• A brief rundown of similar Shopify projects you’ve handled – links appreciated.
• Your estimated hours or fixed price and how you prefer to structure milestones.
• How quickly you can start and the total time you’ll need to deliver production-ready fixes.

I value clear communication, thoughtful troubleshooting and clean code. If that sounds like you, I’m ready to get this rolling today.