Can i be sued for a delinquent debt over 4 years oldin califoirnia?

I just received a summons and it states that i am being sued for $1620 for a debt which is older than 4 years, according to the statutes of limitations in california after 4 years it should be removed right or can they still sue me and if so how can i present my case to the judge or can i write a letter to have it dismissed under this law???