If I have multiple accounts, do I activate 1511CALLBACK service for each account?

ZONE Telecom > Business > 1511CALLBACK
The 1511CALLBACK service is activated by telephone number and not by account.  Therefore users are required to activate the service from their own mobile phones.  Alternatively, you may contact us at Corporate Helpdesk at 67206726 / 67206727 or email us at customercare@zonetel.com.sg for assistance.