Bill increased with no prior notice

I woke up today and saw an email thanking me for my automatic payment, only to see that I had been charged $106 instead of my usual $80 monthly fee. After looking into it, my service plan had its price increased with no prior notice given to me. This is a sudden price increase of over 32% and I would like to have this waived and downgrade my plan to something that costs about the same as what I was paying before.