Employee rights

My employer told me to stop bidding work for a paticluar type of business. So I did. But after building that side of the business for 10 years. I decided to start my own business and take over what they no longer wished to do. I was fired for this. They are saying I may have criminal charges filed but I kept my personal business personal completely separate from my employers business. Didn't use their business accounts as I started my own with my own money. I don't feel I did anything wrong but not tell them about my personal business as it was personal and not work related. I wanted to stay employed while working on my personal business but they decided that wasn't happening. So after 14 years of employment they gave me 4 minutes of their time to discuss these matters.