I found my strong response to unfair blame was helped by better self esteem. If you are an adult and know you did not do something, what another person thinks is not that important. It was only insofar as I had leftover feelings from what my stepmother felt and demanded that I was having problems and working through those issues in therapy got rid of that problem so now I am usually just a bit confused when someone else has accused me of something I did not do as I can't see how I would have done it
I remember in the 1970's when a boss was looking for me and finally found me and asked, "Where were you?" and I explained where I'd been and he replied, "No you weren't; I looked there!" and that threw me into a tizzy because I instinctively knew I had been there but here was someone saying I hadn't been and I was trying to make both "match". Quit trying to make things match! You know what you know; have faith in yourself.