Email [email protected] explaining the issue, mentioning your domain and that you need the Shopify SSL for SaaS churned hostname removing then post the auto-reply ticket number you get here.
It is shopify’s responsibiity to remove these. In practice we see they sometimes do this quickly and sometimes do not know what to do. In instances where they do not know what to do, Cloudflare Support can assist. But, you may get lucky and shopify may be able to resolve the issue quickly. Worth a try while you’re waiting the reply from Support.