A lawyer, but not your lawyer, who wants to correct a lot of misleading and half-baked info in here. Without a condition statement, there’s simply no way to prove what is yours vs. LL’s, even if you have photos/videos. This is almost entirely a he-said-she-said situation, and the landlord is somewhat right about you being responsible for the property that is there. Without the condition statement or asking them to remove it early on in your tenancy, it could be argued you’ve acquiesced to these items being your property.
I see people here mentioning going to court. Depending on how much stuff we’re talking, it simply will not be worth the cost, time, and headache for you. If it’s furniture and you and your roommates/fellow tenants are able to at least put it out on the curb, it will probably be easiest. It will be out of your life and you won’t have a landlord trying to hound you about a bill for removing this stuff. Not the best or most pro-tenant thing to hear and I realize that won’t be popular in this sub, I enjoy sticking it to a bad landlord as much as the next person, but sometimes a practical approach gets this situation out of your life and can remove the stress about worrying if the landlord will also come back after you with frivolous legal action.
In general, security deposits are the property of the tenant and must be used to upkeep/repair the condition of the apartment. It generally cannot be used for rent. Arguably, left behind furniture is a condition in the apartment for the next tenants, and could be deducted. That being said, if you did not receive a receipt within 30 days of submitting a deposit to the landlord detailing the bank and account number where it is being held, you are entitled to demand the entire deposit back in full immediately. If they fail to return the deposit in 30 days, the landlord could be liable for triple damages. Hope this helps