This article outlines how to access your Plesk account through your ExactHosting portal which can be accessed here https://www.exacthosting.com/whmcs/clientarea.php. If you do not have the credentials to login to your ExactHosting portal please refer to this article Reset-your-ExactHosting-Portal-Password.
1) Login to the ExactHosting Portal and enter your credentials.
2) Once logged in navigate to the "Your Active Products/Services" panel and click on the option that contains "plesk-enom-hosting" as the product. Note: You will click on the grey area surrounding said product and not your domain name as that will redirect you to your website.
3) On the "Manage Product" page simply navigate to the bottom of said page and click the "Open Control Panel" button and you will be logged directly into your Plesk account.