Magazine renewal line, If your subscription is expiring they will call you every day to renew it.

Late with your payment?
Debt collectors lately employ call centers to verify your information. They will call you about home alarm, local charity or magazine subscription. Once telephone number and address is verified as valid, the info will be passed to debt agency for a small fee.

This number has been calling at my job for the past few days or so.  I'll answer the phone, but there's nothing but silence on the other end.

This number has been calling my work phone for the past week or two.  There is always silence on the other end - nothing but silence.  Caller ID says it's coming from Concord, NC.

Subscription magazine service.  Call the number back and press 8 to be put on do not call list.