You should get an email notifying you of the ban and telling you why your Google Ads are not running. Meanwhile, you can check Google Ads policy and contact Google support in case they don't have sent you that email.
If your Google Ads account is not suspended, you can also try Google Ads and Shopping free app for Shopify. It helps you to upload all your products to Google Merchant Center and create a feed that will be displayed in Google Shopping ads. Don't hesitate to ask me any questions!