Your answer: As soon as I know that this is a DNC number, I will apologize at once to the customer for the error and assure them that their number will be immediately included in our internal DNC list. I will also make a note in the CRM application so even if the system error happens again the next agent won’t be forced to deal with an escalated problem. I will also report the problem to my team leader or manager as soon as I hang up.