If your posts have vanished from SERPs, it can be due to various reasons such as algorithm updates, penalties, or technical issues on your website. Start by checking Google Search Console for any messages or warnings. Ensure your site complies with Google's guidelines, fix any potential issues like broken links or duplicate content, and consider updating and optimizing your content. You might also want to audit your backlinks and remove any low-quality ones.
For professional help, consider consulting with an experienced SEO company like *Softsolstechnologies**. They can provide a thorough analysis and implement strategies to help recover your rankings.