I volunteer at an organisation that works providing food to low income families (in England). It's a busy environment so we tend to be a bit like robots when on the line - people come in, they get a smile and some food and get moved on so we can serve others. We have social workers who come too to talk to the people and help them access benefits/services etc.

Recently a service user made a complaint about us as a service and me as an individual that we were homophobic towards him and failed to take into account his disabilities when serving him. I have no idea what disabilities he has but regardless my interraction was limited to a greeting, a smile and some food and that was it. An internal investigation of the complaint within the origanisation cleared me of wrongdoing and so the individual changed his complaint to one of "silent homopobia" which I'm not really sure if that's a thing and as a member of the LGBT community I feel very upset about anyway.

The individual is now emailing myself and the complaints officer at the organisation daily complaints about my "silent homophobia" and the fact that I didn't give him an apology at the time (I would have apologised if I knew what I was apologising for and I'm not responding to these emails due to it being with the 'higher ups' at the organisation.) He's now claimed he's "gone to the press" and "reported you to the police" and will "contact your boss" about my "continued discrimination towards him". I have no desire to be named in the press as a "homophobe" especially when I'm not and I don't want to have to go through another complaints process at my job or deal with the police.

Is there anything I can do legally to stop this man's continued vexatious complaints or stop him accusing me of homophobia? I fear this is a situation where I've got to resign from my volunteering or put up with the situation but it's really dragging down my mental health and I don't want to have to quit from my volunteering as I enjoy doing it.

Thanks in advance.