Bad news for Sprint and Verizon customers hoping to get their hands on the Nextbit Robin smartphone.

Nextbit on Thursday announced that it is killing off plans to launch a CDMA version—a.k.a. the one for Verizon and Sprint.

In a blog post, Nextbit CEO Tom Moss said the company has finally fulfilled all its orders for the GSM version (for AT&T and T-Mobile) after several delays. But the CDMA version is facing "a different set of problems, and unfortunately, there doesn't appear to be a workable solution."

If you already ordered the CDMA model, don't worry: you won't lose your money. Nextbit is offering every CDMA backer a full refund.

As for what happened, Moss explained that Nextbit initially wasn't planning to launch a CDMA version, but got so many requests from backers asking for it that they decided to try to make it happen.

"As you can imagine, we were in a rush," he said. "The Kickstarter campaign is only 30 days long, and it wasn't until the second week of the campaign that we realized the demand and started the investigation.

"Because of this, we had to go with the best information we could get before the campaign was over, and over time it turned out that this information was not accurate," Moss continued. "What people at the carriers, in good faith given our need for quick answers, thought would take 'weeks' has turned into 'months.' What they thought would cost 'hundreds of thousands of dollars' has turned into 'millions.'"

Moss said the company still has "no clear answers" about when it would be able to ship the device for these networks, so it has decided to cancel the CDMA version altogether.

"We were too optimistic, too bullish, and as a result we have to deal with our biggest fear, disappointing you, our supporters," Moss wrote.

Fortunately, Kickstarter backers who opted for the CDMA version will get their entire pledge back, including any extras charged for accessories and shipping. If you pre-ordered the device, you're also in the clear: Nextbit has not charged you, and it won't.

As an added peace offering, Nextbit is giving each CDMA backer a 25 percent discount code on one order from the company's online store. If you can't use this discount yourself, you can pass it on to someone else who might like a Robin.

"From all of us at Nextbit, I would like to offer our apologies for this cancellation," Moss wrote.

For more, check out PCMag's review of the Nextbit Robin and the slideshow above.