Notice Of Disparagement From A Company

I got a mail from a company notice of disparagement for the defamatory video that I have uploaded on YouTube ( on your YouTube Channel). I did upload a telephonic recorded audio interview on my channel because the company called me for a Java Technical Lead Position. After clearing 2 face to face rounds, they arranged a 3rd director level interview telephonic. In the telephonic interview the guy was telling me I will be given only software engineer position. I started my career in 2005 as Software engineer and in 2019 they offering the same position even though they sent me a mail for the Java Tech Lead position. I was cheated and it causes serious mental trauma to me. To inform future candidates about this kind of cheating I uploaded the audio along with an email screenshot in the youtube video. I would like to know is there anything illegal what I did. Thanks, Sreejesh