Tenant vacated unit without proper notice (California)

[Ricardo P.]

An inherited Tenant of mine failed to give me a written 30day notice to vacate the property. She was a tenant who was on a month to month lease agreement. She turned over her keys on March 5. On top of that She is requesting a full refund of her security deposit or else she would take legal action. 

1. Ive already followed California state law that requires me to send her a full itemized letter before the 21st day is due. I sent it to her through certified mail+ signature was required. I have my copy just Incase. I did not charge her for any cleaning fees,repairs ect. 

2. I’m keeping her deposit to cover rent for March(deposit isn’t enough to cover this months rent) + 4 days for April. 

30 days in all. 

To make my understanding short she actually owes me money. $950 to be exact.

Is there anything I’m missing before she takes me to small claims court? 

I’ll be filing a counterclaim against her for the rest of the money owed to me if she wants to take it that far.