A trainee teacher from Sutton who was wrongly told she had failed her training course has said her dreams "were shattered" by the news.
Amy Mellors lost her place on a PGCE course in 2015 after she failed a preliminary literacy test - and was told she could not reapply for two years.
Ms Mellors said she is now "looking at legal options" after being told in June that there was an error in the marking, meaning she had in fact passed.
The Department for Education revealed in a review of its system last year that almost 700 people were affected, but this did not help the Sutton trainee.
Ms Mellors, 25, said she was told she had initially failed "by one mark" and that she was "gutted" to learn she had actually passed.
"When I first saw the email I couldn't believe it - it broke my heart", she told the BBC.
"I always knew exactly what I wanted to do and how to get there but failing the test was as far as I could go."
She added she had always wanted to become a teacher, but said her "dreams have been shattered".
After losing her training place, Ms Mellors was forced to take agency work.
By the time she could reapply for the course she had moved from her parents' house, and says she could "not afford to go back into training".
She added: "I have a job in a school as support staff but it is nowhere near the same role or pay scale as a qualified teacher."
A report by the Standards and Testing Agency said 696 people were affected by the marking scheme error between 2014 and 2017 with 528 of them subsequently going on to pass.
In April, schools minister Nick Gibb admitted the marking errors had been going on for 10 years.
Ms Mellors said she has complained to the DfE and was looking at possible legal action.
A spokesman for the Department for Education said: "The exam was immediately taken out of use and the department has contacted a number of people who have been adversely affected as a result.
"The department has been working with those candidates who have now received a 'pass' mark and offered compensation."
Ms Mellors, who was offered £100 from the DfE, added: "It doesn't come close to the heartbreak and the suffering and the financial loss that I've had to endure these last four years."