Click on to the Tenants Union website. It has fact sheets covering just about every situation in renting. There is also a link to a “tenants advocate”.
Armed with the correct information, you might then want to approach Fair Trading for mediation.
But, to answer a couple of your questions, no, a landlord can’t break the terms of a fixed-term rental lease.
And, yes, if you do breach the terms of your lease, you can be evicted.
And yes, if you just up and leave, you can be required to pay the rent on the empty property until such times as a suitable alternative tenant is found, or pay for the costs of advertising for your replacement (or both). Failure to do any of that will quite possibly see you blacklisted.
Now, go to tenants.org.au.