This number called me twice today. I answered however I received no acknowledgement.

This number called me this morning and I said "hello", to no answer.  Then I said "are you wasting my time?" and they hung up on me.  I rang back and it said it was Secure Sentinel - which is a credit card agency that keeps track of all your credit cards in case they get lost or stolen and need to be cancelled quickly.  It is highly unprofessional to ring someone and hang up on them, and I will be submitting a complaint to their company.