Lease Closure

Hi Team I have a registered agreement and have a lockin period of 12 months starting 1 jan 2021. In April, the Tenant has not paid me the Rent, and now has vacated the premises and handed over the keys to me and also taken his belongings from the premises. I havent returned him the security deposit as the lockin clause clealry states 12 months, and the cancellation clause mentions that onus to make good the loss is on the party initiated the termination. Below is the cancellation clause extract. Cancellation: That, Subject to the condition of lock in period (if any), if the Licensee commits default in regular and punctual payments of monthly compensation as herein before mentioned or commit/s breach of any of the terms, covenants and conditions of this agreement or if any legislation prohibiting the Leave and License is imposed, the Licensor shall be entitled to revoke and / or cancel the License hereby granted, by giving notice in writing of one month and the Licensee too will have the right to vacate the said premises by giving a notice in writing of one month to the Licensor as mentioned earlier. To ensure, that he doesn't put a claim on the Security deposit amount, as it should get forfeited due to lockin clause, do i need to formally send him a notice that agreement is now terminated. What action do i take to ensure his claim if any in future for claim on security deposit doesn't hold good and i stay protected. I cant go to registrar and file cancelation deed as he will not turn up for signing. Brgds Basant