Therese Roberts (right) had bought one of the vouchers for her daughter LindsayA woman who spent £750 on vouchers for a Michelin-starred restaurant before it closed fears she may have lost her money.
Purnell's in Birmingham, which became famous for contemporary seasonal food, shut in October.
But more than a dozen people contacted the BBC to say they had been told vouchers, sometimes worth hundreds of pounds, would not be refunded or redeemed.
Glynn Purnell, who ran the restaurant, said he was "heartbroken" by the closure and apologised for what he called a "difficult situation".
Therese Roberts, a retired marketing worker from Coventry, said she bought £500 worth of vouchers for her children last Christmas, before also spending money on a £250 voucher for a friend.
She said she didn't find out the restaurant had even closed until she read the BBC's report on it.
After contacting liquidators, Ms Roberts was told the vouchers were irredeemable and it was not possible for refunds to be issued.
Her request to use them at another of Mr Purnell's restaurants was also rejected.
"I'm really disappointed," the 58-year-old said. "He classes himself as the 'Yummy Brummie'. He blames greedy chains taking his business but he didn't want to communicate or come to a compromise with me.
"I thought he was a better man than that. It's left a rotten taste in my mouth."
Ms Roberts previously visited Purnell's with her husband, describing it as a "great experience".
She said she really enjoyed dining at the premium establishment and wanted her loved ones to be able to try it too.
"He's come across as a down to earth boy from Chelmsley Wood," the mother added of Mr Purnell.
"I thought he would understand what it was like to be an ordinary person in the street."
Ms Roberts was among multiple customers who were told to contact their banks to try and secure a refund, but many received them as gifts and in some cases up to a year ago.
Speaking after the restaurant closed, Mr Purnell said the eatery had been going through "a really tough time" and seen bookings fall by more than 20%.
"Things have moved on and times have changed," he said. "In this current climate, no-one is bulletproof."
But he hinted there could be more to come, adding: "I’m excited for the future and the next steps in my journey. This isn’t the last you’ve heard of the 'Yummy Brummie'."
On Saturday, Mr Purnell issued a statement saying the closure was in the hands of liquidators and questions regarding vouchers must legally be addressed to them.
"I have been very grateful for the support in the unfortunate and unforeseen closure of the restaurant after 17 years," he said.
"We have been advised that refunds can also be requested via customers own banks and credit card companies. I can only apologise for this difficult situation."