If your lease says “as is” then that’s what it means. Many landlords put it in the lease. Anything that is visible (not within the walls) is your responsibility. There are many landlords who wont change a broken fridge or even stove. It is all in the game they play to keep from spending money. There is many a tenant moving with their own Fridge.
If you ask a Rav you should get the psak in writing. He will probably ask you why you didn’t take it off the rent immediately when it happened which is a good question and shayach and he would probably want to see the receipt for the work. It would probably have been acceptable to take it off when it happened and the landlord wouldn’t have had too much to say about it at the time. Taking it off the rent when you leave might be a different issue.