Jenna was given her shift when she was offered the job
A Devon teenager has said she is angry and disappointed after losing the chance of earning about £1,000 in the run up to Christmas.
Jenna Moses was delighted when she was offered four weeks work at the Royal Mail's data entry centre in Plymouth.
But just 36 hours before she was due to start her first shift, the 16-year-old was told the job was not available.
Concept Staffing, the agency which employed her, said Jenna could not work the required shifts because of her age.
But Jenna's mother, Deborah Moses, said Jenna and her friend Jordan Searl, also aged 16, had already been given their rotas.
"Jenna was offered the job after an interview which lasted an hour-and-a-half and included a test," Mrs Moses said.
"She was asked to produce identity, including proof of age, and then given her rota."
Mrs Moses said her daughter was "gutted and angry" to be told the news just 36 hours before she was due to start.
Dan Langford, a spokesman for Concept Staffing, told BBC News the very nature of temping work meant there were no guarantees.
In a statement, he said: "The availability of candidates has exceeded the number of people required and the nature of the shift patterns available meant that those under the age of 18-years-old could not be retained under the conditions of the Working Time Directive."
Jenna and Jordan were due to work from Tuesday to Friday and on Sundays, so it could be the interpretation of the directive which has caused the problem.
It states that young people must have a 48-hour break, but it is not clear whether that break must be uninterrupted.
Jenna and Jordan said whatever the reason, it was little consolation as they now had to try to find alternative employment.
"It was good money, so I was going to be able to get everyone's Christmas presents with it, but I'm stuck now with no money at all," Jenna said.