Can I keep my tenant's deposit as she moved out without paying final month's rent

Tenancy Deposits

Hi,

My tenant paid 2 weeks deposit when she moved in and her notice period is one month as written in the tenancy agreement.

On 12/12/2020, she informed me that she will be leaving the house on 15 of January. I then replied to her that she has to pay next month's rent and cannot use deposit to offset final month's rent. On 14/12/2020, sent me an email saying that she has left the house.

To date, despite multiple email requests, she has yet to pay final month's rent. Please may I know if I am legally allow to forfeit her deposit ? Is she still liable for final month's rent after I kept her deposit ?

Thanks in advance for your advice.