You agreed to rent the property for a term. Most likely this was 1 year. Your point of view of this being overpriced is not relevant, you agreed to the terms.
The landlord has no moral obligation to return any of the deposit if you break the lease.
What's so hard to understand about this? Now you want to damage this person's property?
There are considerable expenses in renting a property out on a long term, not least paying the agent 1 month commission, if he returned your deposit he would be out of pocket, plus all the time spent, plus cleaning, plus bill settling, plus any other contracts (internet 1 yr etc..). does that sound fair?
If you wanted a short term rental then there are plenty of managed service properties out there. The rate you paid reflected a 1 year commitment (due to the costs involved), not a 30 day rent or rolling 30 day. A 30 day rent may of been 75k for all you know at a similar spec'd property short-term.
