They claim that 3.6 million women who were born in the 1950s were not adequately notified that the state pension age had increased to match that of men.
Liz Kendall, the secretary for work and pensions, expressed regret for the 28-month wait for letters, but she has refused to accept any cash compensation.
A parliamentary ombudsman suggested nine months ago that each of the impacted parties receive compensation ranging from £1,000 to £2,950.
The government’s move was called a “insult” by the Women Against State Pension Inequality (Waspi) campaign.
According to the campaign group’s chair, Angela Madden, “the government has today made an unprecedented political choice to ignore the clear recommendations of an independent watchdog.”