breaking a lease in Missouri?

my husband and i rented a duplex in January of this year. we are both disabled. since moving in both of our healths have gotten worse. in the state of Missouri you can only be charged twice the monthly rent rate for a security deposit. we were asked to pay $3,000. we just recently found this out after our doctor strongly recommending we move. i have fallen down the basement stairs 6 times in the last few months and my husband who is a heart patient and has severe neuropathy in both legs and feet has to walk from where we have to park on the street, the driveway belongs to the other half of our duplex, to the front door of our half of the duplex. we found an apartment that is disabled accessible for both of us. our problem is that when we move we were already told by our landlord that we will not get the rest of our rent back that we paid upfront for a year. we are okay with that but what about the deposit. we feel that because we are breaking the lease that the landlord should be able to keep what should have been the legal amount but we were overcharged on the deposit by $1900. can we legally get that back? has anyone been in this situation before in Missouri and what was the outcome?