Owner not returning refundable Security Deposit

I was part of the standard agreement with 11 months lock in period due in Sep'20. But due to pandemic, I along with other tenants, spoke to him on call and told him that we want to vacate as we all are at our home town and flat is lying vacant and there doesn't seem any chance of returning. He agreed to it. After all of us vacated, we message him on Whatsapp to return our deposit, to which he said he is unable to visit the premise yet. After some days, i called him and over the call he told me that he needs 2-3 more days. Meanwhile, a lady who works at his office and used to communicate with us every month for asking for rent etc., contacted us on Whatsapp and sent us contract pictures along with the message that we have vacated before the said 11 months and only after looking at the condition of flat they will settle the deposit. Now, after 30 days, he is telling us that he cannot return the deposit as the contract clearly says 11 month lock-in. He doesn't take accountability of what that lady messaged us. What can I do?