I bought a second-hand house and paid a down payment of 500 thousand. Now I know that the original landlord has defaulted on the property fee for four years.

Do you really have to pay his property fee first and then deduct it from the final payment? This behavior is illegal. Creditor's rights and debts incurred before you took over the house have nothing to do with you. He said that he had never lived, and it was illegal not to pay. According to the current relevant regulations, he has to pay the relevant (not necessarily full) property fees, as well as the creditor's rights and debts between the property and the original owner. The property should negotiate with the original owner or (sue) to recover the debt. Instead of not letting you (the later owner) decorate and move in. Property (enterprise) has no right to refuse to let you decorate and move in. The property and the creditor's rights generated after you take over the house are related to you, and you can also negotiate fruitless (sue) the property company to compensate you for your losses. . .