Citizens Advice is investigating a dispute at one of its bureaux which dismissed a volunteer for complaining about her line manager.
Lettie Fortune had worked unpaid at Lincoln and District Citizens Advice Bureau for six years.
Last year she wrote to Tom James, chair of the bureau, alleging that she and others had been treated unacceptably. James claimed the letter was defamatory and asked her to withdraw it. She refused and was dismissed. She has campaigned for an apology ever since.
"I just want an apology because I was a good unpaid advice worker," she said. "But as a volunteer I had no employment rights. There should be a volunteer ombudsman - volunteers can be shown the door and there is nothing they can do about it."
Fortune has written to Lincoln MP Gillian Merron and the board of the national Citizens Advice organisation in her quest for an apology. Her campaign has been supported by Sue Wing, the bureau's deputy manager at the time, who said Fortune's dismissal did not follow fair procedures and that she was treated "shabbily".
A spokesman for the national Citizens Advice organisation, which can take action against local bureaux, said it was investigating whether "fair, transparent and objective" procedures were followed. He said complaints procedures for volunteers should follow the same principles as for staff. Citizens Advice would comment on Fortune's case after it had spoken to James, who was away, he said.
Third Sector has repeatedly asked the Lincoln CAB to discuss the case, but it has not responded. CABs have recently been involved in two other disputes involving volunteers. One was in York, where a walkout of 28 volunteers led to the resignation of the director and nine trustees.
In March, two volunteer advisers were asked to leave the East Staffordshire bureau following an argument over alcohol at a Christmas party.