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Yes if you want to do it yourself you can.
I would make backups of all files in your public_html folder ( what the public sees )
then delete the files and folders below public_html except cgi-bin using cpanels file manager
or easier your FTP program.
If you have any databases, log in to cpanel > backup and download the databases.
Then cpanel > MySql > delete databases and users.
If you have any problems open a ticket to the techs and ask them to reprovision your account.