Mailchimp today announced that the Mailchimp app, which let its users use their Shopify data to create targeted email campaigns, for example, is no longer available in the Shopify marketplace. The reason for this, Shopify itself says, is that it “had growing concerns about Mailchimp’s app because of the poor merchant experience and their refusal to respect our Partner Program Agreement.”

Clearly, this isn’t the most amicable divorce.

“It’s critical for our merchants to have accurate, complete insight into their businesses and customers, and this isn’t possible when Mailchimp locks in their data,” Shopify explains. “Specifically, Mailchimp refuses to synchronize customer information captured on merchants’ online stores and email opt-out preferences. As a result, our merchants, other apps, and partner ecosystem can’t reliably serve their customers or comply with privacy legislation.”

Unsurprisingly, Mailchimp’s side of the story is a bit different. “Yesterday, we asked Shopify to remove the Mailchimp for Shopify integration from their marketplace,” the company wrote. “We made this decision because Shopify released updated terms that would negatively impact our business and put our users at risk.”

Mailchimp says it refused to provide Shopify with all the customer data it asked for because Shopify’s terms simply weren’t fair or practical.

“We have been negotiating for months with Shopify on trying to get terms that were very fair and equitable to both of our businesses — and there were several points that we just weren’t willing to compromise on,” Joni Deus, Mailchimp’s director of partnerships, told me. “Anything that hurts our customers’ privacy was a non-starter for us.” She also told me that Shopify specifically asked for pretty much any data Mailchimp collects about its users, including data it collected in the past since the app was installed. “We had no way of getting that consent from our users retroactively,” Deus noted.

There may be another wrinkle to this story, too. In recent months, Mailchimp partnered with Square to launch its shoppable landing pages. That puts Mailchimp deeper into the e-commerce business and into competition with Shopify.

In its statement, Mailchimp argues that it integrates with more than 150 different apps and platforms. “We won’t compromise on that just because Shopify sees it as a competitive threat,” the company wrote. “We want people to have choices,” Deus added. “The marketplace is starting to collide and people are starting to compete with each other. Many of our other partners are also in our space and we would never limit a competitor from what they were willing to do for their business.”

In the end, we’ve got two companies that both argue they are putting their customers’ privacy first. This doesn’t strike me as a conflict where there was no reasonable compromise to be had, though, so in the end, it’s now on both companies’ customers to figure out what to do next.

For users, there are still plenty of other options, including the use of third-party integrations that link the two services together, including Zapier, Automate.io and ShopSync. Indeed, using those is Mailchimp’s recommendation for its current users.