What can I do?

I was working for the same telecommunications company for almost two years. I was great at my job. I had a romantic relationship with a co-worker that ended up being promoted to a higher position. We ended terms on bad conditions. She was very close with our head manager and often didn’t assist me or perform the tasks she was required to do when it came to my job or questions. When I was fired, I was included with a list of other employees that didn’t meet the quotas however I met all quotas and exceeded my requested performance stats. I feel that I was wrongfully terminated and had my ex never been given a position of power then I’d still have my job.