Leanne Jones, 28, partner Andy Payne, 31, and sons Harrington, five, and Hudson, 18 months, have been buying and collecting the gift cards - now totalling £800 - for nearly three years.
Instead of presents and gifts for birthdays, their engagement and Christmases, they have asked family for vouchers towards their dream break in Disneyland Paris in December.
Even Harrington paid towards the trip as every time his piggy bank reached £40, he took it to be swapped for vouchers towards the trip.
But the collapse of Thomas Cook this week means the vouchers are now worthless and the family's plans of visiting the 'Happiest Place on Earth' are over.
Leanne, from Milton Keynes, said: "To find out our dedicated saving for the past two-and-a-half years has all been for nothing is absolutely devastating.
"We thought it'd be easier to save for the holiday of a lifetime if it was in vouchers rather than money that we could dip into.
"We thought it was a really savvy way of saving money for a holiday, and told all of our family and friends that if they ever wanted to get us presents, then we'd really appreciate Thomas Cook vouchers.
"We started off by asking for the vouchers at our engagement party in May 2017, and since then, every birthday and Christmas saw us getting more vouchers."
Stay-at-home mum Leanne and road worker Andy dreamed of taking Harrison - a huge Aladdin fan - to Disneyland.
The couple welcome baby Hudson in July 2018, and continued to save their vouchers for a trip that both boys would enjoy.
Hearing of the collapse, Leanne tried to contact Thomas Cook, and when she couldn't get through, rang ATOL.
People who had already used their Thomas Cook vouchers but had not yet been on the trip were ATOL protected and will have their cash refunded.
However, for people like Lyndsey who had not yet booked a trip, their vouchers are now worthless and are not ATOL protected so the family will not get any money back.
"I'd been following the news for a few days, but the CEO of Thomas Cook appeared so confident that the company would survive, I believed him," she said.
"I thought, 'it's Thomas Cook, they'll never go bust' and besides, being a busy mum of two little boys, I had no time to quickly go book a holiday just in case.
"There was still a Thomas Cook shop open in Milton Keynes so I rushed down there but they told me the vouchers were totally worthless now."