You begin counting the three days on the first day after the day the notice was served.  Saturdays, Sundays and legal holidays do not count.  So if you were served on a Friday you start counting on Saturday.  Sunday and Monday do not count here.  So you should have paid on Tuesday not Wednesday.  Answer the unlawful detainer action and seek help here.  You are being evicted.  Here is a link to review.  Good luck.http://www.dca.ca.gov/publications/landlordbook/terminations.shtml