You have no guarantee. Now that you have given him 20W, you must deal with it. First of all, you should make sure that his house has no other mortgage except170 thousand yuan. Well, go to the trading center and pull a property right certificate survey, which will show it. If not, you go to the bank with him to decompress, and after decompression, you take away all the information, so even if he wants to take away the real estate license privately, it is impossible. Then you can follow the sales contract process. Before you go, go to the law firm to consult the prosecution intermediary to see if you can get the corresponding compensation, which is caused by the intermediary's work mistakes. After finishing the account, directly sue the intermediary.

If the decompression is finished and the owner doesn't want to transfer, then you can take all the information and go through legal procedures, so there will be no confusion. The owner will either pay you back or give you the house.

If there are other mortgages besides this 65,438+0.7 million, then you must give up the transaction and directly sue the intermediary and the owner.