You can probably NOT recieve a refund of rent paid.. further the lease is voidable by you if you want. In defense for eviction if you plead that the house is not habitable and it has no CofO you can void the lease ... however if you plead it right you may be able to force the landlord to 1) pay your moving costs (after all you are moving only because there is no CofO) and 2) pay any difference in rent until the end of the lease (you had a signed agreement at a specific rent until the end of the lease)
also I would reccomend that you invite the local city building officials in to the house to inspect it!
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