A subsidiary of Visa, a key Obama campaign donor, that specializes in credit card transactions has abruptly stopped servicing the nation’s largest gun store after four years because the store sells guns, a fact the owners never hid.

Hyatt Gun Shop of Charlotte, N.C., told Secrets that the subsidiary, Authorize.net/CyberSource, simply sent an email to owner Larry Hyatt to announce that it was suddenly breaking off the business relationship. The reason: “The sale of firearms or any similar product.”

The company email said that gun sales violated a section of the service agreement the two signed over four years ago and after Hyatt went into detail about its sales and products -- and name.

“We’ve never seen anything like this,” said Justin Anderson, Hyatt’s marketing director. He said it took a week and thousands of dollars to line up a “gun friendly” credit card processor for online sales.

The brushoff of Hyatt's business has sparked a national boycott effort against Authorize.net and parent company CyberSource organized by the website Grass Roots North Carolina. “It looks like the small but noisy anti-gun crowd has gotten to what must be a jelly-spined PR department at CyberSource and Authorize.Net. Either that, or leadership at these companies have simply become anti-gun all on their own,” said the website in announcing the boycott.

Anderson suspects that the company, purchased by Visa in 2010, got cold feet dealing with a leading gun seller and he said that he's heard of other gun stores being dropped. The company had no immediate comment.

The sudden move comes just two weeks after the Washington Navy Yard shootings which were followed by a plea for more gun control from President Obama.

Several Visa executives contributed to the president’s re-election campaign. Their total was $21,780, according to the Center for Responsive Politics.

Below is the short email notice from Authorize.net:

Dear Hyatt Gun Shop Inc,