You are using Managed WordPress so there isn't a cPanel - To reset the site you have 2 different options.
1) Install a WordPress Reset plugin - this will keep your install / plugins / file but reset the database
2) You can delete the install all together and then setup a new site
Check out my site! | I currently manage over 300 WordPress Websites
* Please note that I offer free advice on this forum. Thank You Info If you would like personalized help, please contact me. Otherwise, please ask your question in the proper forum so the answer can assist EVERYONE in the community and not just you. Thanks! *
Once your issue is resolved,
please be sure to come back and click accept for the solution