Debt Collection details kept secret

I have been attempting to get in touch with the customer care team and no one can give me the direct contact details (phone number, or email address) of the national security corporation limited so that I can arrange to pay .

I have had this account for more than 8 years and have fully paid up the account on more than one occasion , I am disappointed that my pursuit to clear the balance is in vain as how do I know if my payment has been received and acknowledged if I dont have a contact point.