Although her baby was unharmed, Mrs Cobb said she felt horrified at the risk her daughter could have faced had she been involved in an accident.
"I just keep getting these images in my head. All I could think about is that my sister just had her baby and we were going to go down to Wellington and imagine if I had taken her down there and we were involved in an accident and my baby ended up flying straight past me and into the windscreen. The thought of it is still haunting me."
Mrs Cobb said she immediately contacted Top Deal Store after the incident and was appalled at the response she received.
"It has all just been a nightmare and the response I got.. I just can't believe it. My baby could have died. I just can't imagine if someone else who bought a seat was to be in a serious accident [and their child was injured], who is to be held accountable for that? You can't bring back a life once it has been taken."
A statement issued by Toptoys NZ Limited director Kirstin Yu said she apologised to the Cobbs family for the unfortunate incident and planned to travel to Taupo to meet the family in person and retrieve the faulty product for further examination.
"All products involving Delux 3 in 1 car seat will be pulled from the market immediately until Toptoys is satisfied it is safe to sell them. The products will be returned to its manufacturer in China for safety reviews."
The company also planned to provide the Cobbs family with a full refund.
This was the first complaint the company had received about the car seats and they were very popular among customers, Ms Yu said.
"We sell lots of these car seats and different seats from different manufacturers. Lots of people [have bought this seat]," she said.
A spokesperson for 1st Care meanwhile said "this is an occasional problem, not all of our products have problems".
She would not comment further on the issue.
Following the incident Mrs Cobb took to social media with a demonstration video of her testing the car seat.
The video shows her strapping Lyric-Brooklyn into the seat and then tugging on the belt. Twice the buckle comes undone when she pulls on the straps.
The video was accompanied by a chilling message from the mother of three warning others about her experience and the risk of faulty car seats.
The post has since gone viral having garnered more than 50,000 views and hundreds of comments of support.
"The response has been overwhelming. So many people contacted me wanting to know if I needed a seat to borrow."