Thousands of runners due to take part in the Cardiff 10k will not be offered refunds after the race was cancelled.
Organisers Front Runner Events said delivery of the event, due to be held on 4 September, was "more challenging than anticipated".
The company said it "cannot defer, transfer or offer refunds to runners" due to the money already spent.
"As frustrating as this is, we were not expecting so many challenges," said Front Runner boss David Martin-Jewell.
The race, expected to attract around 7,000 entrants, will be replaced by a "virtual event" starting on 7 August and ending on 11 September - exact details of which have not yet been confirmed.
"Despite having explored a number of alternative options and scenarios... we simply have not been able to find a viable solution," said Mr Martin-Jewell.
"Front Runner Events have already committed to a number of large orders in relation to the event, which are required due to the lead-in times from suppliers.
"Unfortunately, therefore, we cannot defer, transfer or offer refunds to runners due to the monies committed or already spent."
"However, there will be a virtual event to enable runners to make the most of their training and fund raising efforts," Mr Martin-Jewell added.
"We are confident that the event will continue to grow when it returns in 2023.
"We thank you for your patience and understanding."
Runner Janine Parry, a member of She Runs Cardiff, said offering no refund was "not good enough".
She said: "I've paid £28 for an event they've decided to cancel, yet they expect me to go out and complete a 10k, which I then need to submit evidence of doing, so they can send me my T-shirt and medal.
Ms Parry has been left "furious" by the situation.
"I want my money back so I can pay to enter another race that's actually going ahead," she said.
Laura Stephenson was planning to use the event as training for her first half marathon.
She was hoping it would help her get used to running with thousands of other people, which she finds daunting.
"The virtual event they're offering instead is not only far too expensive, as they're keeping the whole entry fee, but also doesn't support my reasons for entering," she said.
Alan Mason, of Les Croupiers running club, said the offer of a virtual race was "derisory".
"Virtual events have nothing of the atmosphere and excitement you pay to enter big city centre races for," he said.
"They also rely on people having a GPS watch, which not everyone will have.
"I'm sure a lot of people will be feeling the same as me. Some of them will live elsewhere in the UK, so this affects our city's reputation."
The race was granted a licence by Welsh Athletics.
Chief executive, James Williams, said there had been a delay in people returning to mass participation sport as the nation recovered from the pandemic, and that the cost of putting on events was going up.
He encouraged councils to support event providers.
Sponsors Cardiff Metropolitan University have been approached for comment.
It is the second mass-participation Welsh running race to be shelved in a matter of weeks.
In July runners were told the Newport Marathon and 10k, due to take place in October, had been postponed by organisers Run 4 Wales, due to "a number of operational risks".
The races were rescheduled to 2023, with runners already signed up able to transfer into the rescheduled races free of charge or request a refund.