What can I do if landlord is forcing to pay rent?

I’ve rented a commercial property from Nov’2017 for setting up a store. I’ve not paid the rent during COVID lockdown in 2020 when businesses were closed. Landlord is NOT returning my deposit when I’m planning to sell my store off now. Asking me to pay rent for lockdown period (2 months rent). I’m willing to pay half rent but they are insisting on paying full. Also, they promised me a lift as store is on first floor and they never installed it in last 6 years. I lost lot of business because of it as it’s related to Moms and Kids segment.