I'm sorry to hear that, I know it must be frustrating. Here at Shopify, we would not have further insight into why Printful has added a restriction to your account, as they are a third party service and have their own Terms and Conditions in place. I can see from their help centre that Printful is not available in some countries because of legal restrictions or shipping carrier limitations. Or if they think the content of your printed items violates their Acceptable Content Guidelines or infringes on the copyright or intellectual property of others, they may also restrict your account in this instance. Printful's full Terms of Service is here if you'd like to fully read through it!
In your case, I would recommend reaching out to Printful directly to find out for sure why there is a restriction on your account. It may have been added wrongly, so hopefully, they can remove the restrictions for you and you can continue to build out your store! You can email firstname.lastname@example.org to contact the team directly, I would recommend sending a detailed description of the steps you're taking to try and connect your products to Shopify, and a screenshot of the error you're seeing that is saying there is a restriction on the account. This will give them further context on how to solve this for you! Alternatively, you can start a live chat with their team here if you prefer for a more instant response.
In the case that Printful is unable to remove the account restrictions, we do have a full range of Print on Demand apps here that you can use as an alternative! I do hope Printful will be able to resolve this for you, but it's always good to have a backup plan in place to make sure you can continue with your business.
Let me know how you get on!
Ava Social Care | help.shopify.com
Ava | Social Care @ Shopify - Was my reply helpful? Click Like to let me know! - Was your question answered? Mark it as an Accepted Solution - To learn more visit the Shopify Help Center or the Shopify Blog