An estimated 38,000 telephone customers who selected a long-distance carrier other than Hawaiian Telcom earlier this year but ended up with Hawaiian Telcom anyway will be reimbursed or credited for domestic and international long-distance calls they made from May to Nov. 4.

Hawaiian Telcom is sending letters to affected customers explaining that "a processing error by Verizon (Communications Inc.)," the former owner of Hawaiian Telcom, led to the mistake.

Verizon sold most of its Hawai'i business to Hawaiian Telcom in May.

At that time, telephone customers had the opportunity to pick new domestic and international long-distance carriers.

Because of a processing problem, an estimated 38,000 customers who wanted other long-distance carriers ended up with Hawaiian Telcom, according to Verizon Communications spokesman Bill Kula, who is based in Dallas.

Customers who wanted other domestic or international long-distance carriers will be reimbursed an estimated total of $200,000, Kula said. Verizon will be responsible for that cost, he added.

Hawaiian Telcom began sending letters to customers on Friday, telling them that they will be switched to the long-distance carriers they originally wanted on or about Nov. 4.

Hawaiian Telcom spokeswoman Ann Nishida referred calls to Verizon officials.

The credits and reimbursements affect about 6 percent of the 645,000 telephone lines of customers who were given the opportunity to switch long-distance carriers when Verizon became Hawaiian Telcom.

"Customers who were provided long-distance service by carriers other than whom they wanted will be credited or refunded for those calls placed," Kula said. " ... Verizon regrets that the computer programming error occurred — first and foremost. All of the affected lines will be restored to their authorized service providers at no charge to the affected customers."

Hawaiian Telcom's letters also ask customers to contact their new domestic or long-distance carriers after Nov. 4 to make sure the switch took place.

"That's fairly standard in the industry for consumers to ensure that they've enrolled in the plan that they've requested," Kula said.

Kula said Verizon officials also notified the state Public Utilities Commission and Federal Communications Commission about the situation.

"We identified the problem ourselves and made Hawaiian Telcom aware of what took place and — based on our dialogue with one another — set forth to ensure that consumers and the state and federal regulatory agencies were apprised of the situation," Kula said.

Reach Dan Nakaso at dnakaso@honoluluadvertiser.com.