If you have any automatic debits on your accounts or on your credit cards – cancel them immediately
Instruct your bank and credit cards to be on the lookout for fraudulent attempts to access your accounts.
Send a certified mail to the registered place of business for this company addressed to the registered agent for the company and instruct them that you have terminated the agreement and the day and date and time you did so.
Keep copies of everything. And keep precise notes of any phone calls.