Javelin hasn't so far provided the templates for either the opt-in e-mail or its campaign e-mail to Emailappenders, Cooper said. An analysis could show that the templates ranked as too spammy.

It's also possible that SwiftPage had a technical problem; Cooper said he's also asked for the IP (Internet protocol) addresses the campaign was sent from, as it could be checked to see if certain ISPs put up a block. Javelin hasn't provided those either, Cooper said.

"I know the list is not the root cause of the problem," Cooper said.

Cooper said he verified the addresses on the list after Javelin complained. He sent an opt-in notice for his own company, Emailappenders, and the list came back as being 70 percent good -- the deliverability rate guaranteed to Javelin.

Emailappenders will send an e-mail campaign on the behalf of a client. ISPs will sometimes block the e-mail as spam. But the company has a special team that contacts ISPs to ensure it's not labeled as a spammer, Cooper said.

Cooper said a refund is not out of the question, but he's more concerned about Emailappenders' reputation after Javelin quickly struck back by issuing a scathing press release on Tuesday. Emailappenders is a 14-year-old business, he said.

"We can’t keep 100 percent of our clients happy, but no one has reacted like Javelin Marketing," Cooper said.