Hailey and Ty Hampton lost one of their twin boys, 13-week-old Liam, in February. "He was our little baby, our little cuddle buddy," said Ty. For Jonathan and Amanda Butler, it was their 10-week-old daughter Arya in January. "She was perfect; Arya was perfect," Amanda said.

Jonathan added, "I don't go a day without thinking about her."

K.C. Connolly's 6-week-old son Jameson, a twin to sister Dorothy, died in 2015. "There's not a time I don't think about him," she said.

All three families are suing Fisher-Price, saying their babies died in a Rock 'n Play inclined sleeper.

The company and the Consumer Product Safety Commission announced a recall of around 4.7 million sleepers in April, after reports of more than 30 infant deathssince the product's 2009 introduction.

Hailey Hampton said she and the other parents were speaking out to raise awareness: "There's people out here that are still using the Rock 'n Play Sleeper that our children died in."

"This is a fundamentally dangerous product that shouldn't be on the market," said Dr. Ben Hoffman. He and other pediatric experts say the device, although marketed as a sleeper, was never safe for infant sleep, in part because of its angle.

"Knowing what we know about babies' relatively large heads, relatively weak necks, the upright positioning can lead to the head flopping forward and that can block the airway, which is devastating to babies," said Dr. Hoffman.

Fisher-Price told CBS News, "The loss of any child is tragic and heart-breaking.  Safety is our highest priority."

Another company, Kids II, also recalled some 694,000 sleepers in April after five infant deaths. But a new survey released by the U.S. Public Interest Research Group (PIRG) has found one out of 10 surveyed day cares nationwide still using recalled sleepers from Kids II and Fisher-Price.

Consumer investigation correspondent Anna Werner asked, "What does it say about the recall system in this country that you were able to find these sleepers?"

"It says that it's not working," said U.S. PIRG's Adam Garber. "And if we are going to keep children safe, we have to make sure that we can get these products out quickly and efficiently."

Both Fisher-Price and Kids II said in statements they've taken multiple steps to notify consumers about the recalls.

Kids II says it sells "to retailers and consumers for single family use only."  Fisher-Price said it has "reached out to companies on the secondary market… urging them to take action to prevent unlawful resales" of its sleepers.

Yet, "CBS This Morning" found numerous postings selling them on Facebook, Craigslist and eBay, some from parents who still seem to believe they are safe.

That's why these parents told us they're speaking out in an interview for the first time.

Hailey Hampton said, "If we could at least help one family out of all the other ones that are still using the Rock 'n Play, maybe that's what I'm here for."

Jonathan Butler said, "We don't want another baby to die because of the Rock 'n Play."

Werner asked Ann-Marie Buerkle, acting chairman of the Consumer Product Safety Commission, "Is this process working well enough to protect these kids?"

"I think it is. I think it is," she replied. "I think in some cases and perhaps this one, it's been a frustrating path."

"Do you worry about the sleepers that have been recalled that are still out there?" Werner asked.

"I do worry. There's a lot of parents out there who may have knowledge of the recall, but they love that product. And I would say to them, please don't use the product."

But the parents we interviewed blame Fisher-Price itself for some of the confusion, pointing to a statement the company issued at the time of recall saying that parents or caretakers used the product "contrary to the safety warnings and instructions."

Of the statement, K.C. Connelly said, "It's like they gave me this little something of taking these death traps off the market, and then took it all away."

Reports to the CPSC show some infants did roll over in these sleepers and were unrestrained, but all the parents we interviewed who are suing Fisher-Price say that was not the case with their babies.

Dr. Hoffman, with the American Academy of Pediatrics, said these inclined products are not safe for babies to sleep in unmonitored, under anycircumstances.