The online service has been unavailable for almost two weeks in parts of Maryland, Rhode Island, Virginia, Colorado and Washington, prompting ongoing frustration among eFax customers.
Representatives for eFax were not immediately available for comment.
"I have been extremely frustrated by this and it is affecting my business, as I cannot receive faxes," said Joshua McDermott, president of M3 Partners, a small consulting company in Providence, R.I.
"I would tolerate such an outage if I were using the free eFax service, but I am a paying customer. What really burns me is not only the duration of the problem, but the lack of information about the status of the resolution."
eFax, which charges U.S. and U.K. subscribers a $4.95 monthly rate plus various fees, has posted information on the outages on its Web site.
"We are experiencing problems with (busy signals) when calling numbers in these area codes," the site reads, referring to numbers in the 240, 401, 703 and 720 area codes. "Not all numbers in these areas are affected. The phone carrier has been contacted."
The site states that earlier power outage problems in Washington have been resolved, but service is still slow in the area. "In the meantime, faxes which arrived during the outage are being delivered on a first in, first out basis," the site states.
The outages are an added blow to the company's recent problems. The Menlo Park, Calif.-based company nearly ran out of cash earlier this year. Then-rival Jfax loaned the company $5 million before the two companies merged in July. Shares of the company have sunk below $1 on the Nasdaq stock exchange.
Meanwhile, customers may seek alternatives to eFax's service.
"I've worked in the support business for several years," McDermott said. "And if I provided this kind of service, I'd be out of business."