If you haven't signed a lease then you may be able to get out of the lease but it will depend on a close examination of your situation and exactly what you negotiated with the old tenant and landlord. Only a fully briefed lawyer can give you a firm answer on that question, but I think if you engage a lawyer they would have good prospects of negotiating a way out on a reasonable basis. In any event, I would certainly recommend you NOT sign any lease document until you have sought comprehensive advice.
Even if you cannot simply walk away from the lease you you should still be able to get out once a new suitable tenant is found.
Regardless, you are unlikely to be able to recover any of your expenses in refitting the property for your business and would ordinarily have to pay to reinstate the property to its original state when you first moved in.
Your situation is somewhat complicated because you have contractual obligations and general legal obligations which may affect how this resolves. If you cannot reach a simple satisfactory exit with the former tenant and landlord, then I would strongly recommend engaging a suitable lawyer to review your case in detail. Litigation is a possibility, but a good lawyer should give you a good chance of negotiating a satisfactory outcome.
If you need help locating a suitable lawyer, contact the WA Law Society:
I trust the above assists.
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