Fired after 3 months while still in training - IT Support Security Innovation Employee Review

I was hired for my 22+ years of customer service and was told that I wouldn't need to be technical. In fact, my manager passed off my training to his family member who he got hired for the 5k bonus they both got. That person stopped training me at month 2 and became relatively hostile. I later learned he received the 5k bonus for backfilling my role with his friend. Though he was a bartender before this, he was able to do the role; however, they felt that it was determined at month 3 I could not. The man who hired me and HR called me 2 days after I requested PTO to inform me I was being fired. I asked HR to provide any documentation that I was not meeting my metrics. Nothing has been sent to me since.