If you're done testing HostBill, and like to start with clean state but leave your settings & products configured intact, use SQL queries below on HostBill database to clear unwanted data:

TRUNCATE hb_tickets;
TRUNCATE hb_ticket_replies;
TRUNCATE hb_tickets_notes;
TRUNCATE hb_tickets_attachments;
TRUNCATE hb_client_access;
TRUNCATE hb_client_billing;
TRUNCATE hb_client_details;
TRUNCATE hb_client_fields_values;
TRUNCATE hb_client_files;
TRUNCATE hb_client_privileges;
TRUNCATE hb_client_credit_log;
TRUNCATE hb_client_activity_log;
TRUNCATE hb_client_changes_log;
TRUNCATE hb_accounts;
TRUNCATE hb_vps_details;
TRUNCATE hb_subscription_items;
TRUNCATE hb_accounts_addons;
TRUNCATE hb_config2accounts;
TRUNCATE hb_cancel_requests;
TRUNCATE hb_account_logs;
TRUNCATE hb_accounts2servers;
TRUNCATE hb_domains;
TRUNCATE hb_domain_logs;
TRUNCATE hb_orders;
TRUNCATE hb_order_items;
TRUNCATE hb_order_log;
TRUNCATE hb_order_steps;
TRUNCATE hb_transactions;
TRUNCATE hb_invoices;
TRUNCATE hb_invoices_log;
TRUNCATE hb_invoice_items;
TRUNCATE hb_recurring_invoices;
TRUNCATE hb_creditnotes;
TRUNCATE hb_email_log;
TRUNCATE hb_aff;
TRUNCATE hb_aff_commisions;
TRUNCATE hb_aff_logs;
TRUNCATE hb_aff_orders;
TRUNCATE hb_aff_widlog;
TRUNCATE hb_aff_coupons;
TRUNCATE hb_upgrades;
TRUNCATE hb_config_upgrades;
TRUNCATE hb_coupons_log;
TRUNCATE hb_mettered_reports;
TRUNCATE hb_mettered_values;
TRUNCATE hb_mettered_sync;
TRUNCATE hb_notes;
TRUNCATE hb_oslicenses;