Asking for Security deposit after 1.5 yrs

[Neeta Agrawal]

For context, we gave the tenant a 60-day notice for non upkeep and no repair communication in 2023 and then extended it for 30 days upon his realtor's request, setting the move-out for May 31, 2023. The tenant refused to communicate about his plans to vacate and finally left the key under the mat on June 2 but made no communication, so we had to make 4 trips looking for the key. He left his belongings inside and later texted his intent to pick up his stuff. He also requested a walk through for later in June. We had previously agreed for a walk through on 31st May, but he hadn't completely vacated. On June 7th, we sent an itemized list of deductions via text; he responded on June 8th, disagreeing and threatening legal action. We didn't reply. Now, over a year and a half later, he sent a certified letter last week demanding the security deposit or legal action within 30 days.

Please advise.