If a formal rental contract is not signed: ① report the landlord's tax evasion, call the local taxation bureau or the tax service hotline 12366 ② report the illegal building, and call the urban construction service hotline 123 19 ③ to collect evidence and file a complaint. If a rental contract is signed, you need to check the agreement in the contract, and if the tenant defaults, whether to refund the rent or deposit that has not been rented; If there is an agreement in the contract that the tenant will not refund the rent and deposit in case of breach of contract, then even if you take up legal weapons to safeguard your rights and interests, there is no way. After all, it has been agreed that if you breach the contract, the relevant treaty will not be returned. (2) There is no agreement in the contract that the tenant should bear the liability for breach of contract and can negotiate with the landlord to get back part of the rent or deposit; If you turn your face, you can take a loophole and get back the rest of the rent or even the deposit according to the fact that you have not signed a rental contract, depending on how it is agreed.