Hawaiian Telcom Inc. is coming under fire from some customers who say a company program allowing them to keep their account data private isn't private enough.

Hawai'i's largest telephone company said it has received at least a dozen complaints about the program, which asks customers if they'd like their account information excluded from data Hawaiian Telcom shares with marketing partners.

People who want to keep that information private are being asked to check a box on a postcard and mail it to an address in Honolulu.

But some customers object to having to detail other information on the postcard, including their names, telephone numbers and billing addresses. The postcard must also be signed.

"It's open in the mail when the the government and everyone else is telling people not to reveal any personal information," said Rowena Nakamitsu, a Hawaiian Telcom customer who said she worked for the company more than 20 years ago. "Why didn't they give a self-addressed envelope like everyone else does?"

Hawaiian Telcom said it is required by the Federal Communications Commission to ask customers if they want to opt out of promotions, and the FCC says a reply postcard is acceptable.

"My understanding is that (previous company owner) Verizon had a call-in number for replying," Hawaiian Telcom spokesman Dan Smith said.

"Based on the customer feedback, we'll be looking at the possibility of using some other approach next time."

Smith added that marketing partners can't use the information for any work except on Hawaiian Telcom's behalf.

The data is used to better target customers for specific products. Someone who is making a lot of calls to the Philippines, for example, may get a special long-distance offer. The data can also be combed to send offers to people who don't use the company's high-speed Internet services, or identify someone who might buy a package of services from Hawaiian Telcom, Smith said.

The state Public Utilities Commission said it had received at least three complaint calls about the postcard. Honolulu resident Lynne Matusow said she recognized the information on the back of a postcard was sensitive, including requiring her to give an apartment number that isn't included in her telephone directory listing. She hand-delivered the card to the company in an envelope.

"It is information that could be used by an identity thief if they got a hold of it," Matusow said. Another customer, Marilyn Vrana, said she was sending it in an envelope also.

The protests comes at a time when Hawaiian Telcom has generated other customer complaints about billing problems, including double billing.

Smith said the company had set up a line for people to call, 643-3267, if they want an explanation of the opt-out postcard.

Reach Greg Wiles at gwiles@honoluluadvertiser.com.