Shopify Store Maintenance & Content Fixes

I need a professional to diagnose and fix my Shopify store. I've identified a corrupted robots.txt file that requires immediate attention. I am looking for a monthly maintenance service to keep my store in optimal condition. We have a lot of product contents that needs to be updated with pricing and details. You must be able to set up taxe collection for each u.s states that purchase from my site. Also knowledge of best A.I apps to help customers buy products and email reminders to our customers. (Pleased I need someone that can speak English well because I might need to contact you often about my site.)