Can a claim for unemployment benefits be backdated?

I was terminated from my jobs following my maternity leave, had no knowledge really of unemployment until I reached out for help, from the state who informed me of unemployment, I filed was denied went to a hearing and won but when I filed my claim it was several months later, my job never informed my of my right to file, I wrote a letter for back payments and was denied, now I'm going to appeal this letter, what are my chances?