How do i contact decision health customer service? Customer Service. Hours: Mon-Fri. 9:00 a.m. - 6:00 p.m. ET Toll-free: 1-855-CALL-DH1 (1-855-225-5341) Local Calls: 1-301-287-2682 Fax: 800-785-9212 Email: [email protected]. What is the email address for the department of hdc? HDC Department Extensions Department/Office General Number Email Estate Management 1000 [email protected] Settlements & Community Relations 1300 Allocations 2000 [email protected] Finance 2200 23 more rows ...How do i contact hdc new zealand? You can also use the New Zealand Relay Service (TTY?HDC/VCO/Internet relay) to contact HDC. To call us using the New Zealand Relay Service: Dial New Zealand Relay Service — 0800 40713 713 (TTY) or 0800 40715 715 (voice) To find out more about the New Zealand Relay Service, click here.What happens when you make a complaint to hdc? When you make a complaint to HDC it will be given to a Complaints Assessor. A Complaints Assessor is someone who looks after your complaint. Click here to find out more about what happens after you make a complaint to HDC.