Bit of a rant!

I would love some advice/ perspective, and also to have a bit of a rant so apologies in advance!

I did some admin/project management work a few months back, on a part-time, (10-15 hours a week) freelance basis. while the work was basic admin, the person i was working for was very disorganized and not a good communicator.

Long story short, the project went to pieces and was a bit of a disaster.

I have worked for years in the arts, festivals and events. When I initially took the job on, I expressed some doubts about the size and scale of the project, but the person employing me assured me that they were confident that they had the backing of various other parties (don't want to go into too much detail obviously)

I was cautious about the project, so I got a list of what was expected of me and my duties in writing. I was working for about 4 months, in this time I only met the person employing me in person twice, and they were almost impossible to get by phone or email. a week or two before the end of the project, when it had all fallen apart basically, they went completely awol. Afterwards they admitted that they had lost the plot, been stressed out and had gone drinking all weekend, avoiding my calls and emails.

I felt bad for this person initially, at the end of the project and of my term of employment, as I knew they had lost money. But a lot of the fears I had expressed at the beginning of the project turned out to be true, and I felt that i had done a lot more than my job description entailed.I sorted a lot of things out while I was unable to get in touch with them, that weren't really my responsibility. I also found out that this person had tried to run a similar event to this one, that had failed, for similar reasons (lack of interest etc). So I felt that it had been silly of them to do the same thing and expect a different outcome, and to ignore any advice.

Since then, I have found out that he has been slagging me off and blaming me for the failure of the project, saying I have lost him money etc, that I was lazy and didn;t do my job. I know this because colleagues in the industry have told me, I have a good work reputation and I feel really angered by this, obviously. I would like to confront them, but feel that it is maybe a waste of energy, as this person is very deluded and has a major ego. The people who have told me about what he has been saying about me know me, and my work, and one person in particular called him on this when he was slagging me off, saying that they knew me and that it didn't sound like me to let a project fall apart. So it is not that I am worried for my professional reputation, luckily I have a good reputation and he does not, so in that regard it is fine. he has fallen out with lots of people he has worked with, and I haven't so it just looks bad for him

But i am still really annoyed, and feel like I would like to email him and call him out on this. Or maybe I should just GET OVER IT! what do you think ? this has never happened to me before and it is really getting to me