How to sell a house with the participation of "parent capital"

The fact is that the seller is obliged to initially issue the property to the buyer. Only after that the buyer goes to the pension fund with a statement about the transfer of the funds of the "parent capital" to the merchant's bank account.
Most bona fide buyers do this. But there is such a category of people who decided that once the real estate is in their property, you can keep this amount of money for yourself under the pretext that the housing they bought is not worth the money that was the original contract drawn up and certified according to all the rules, or any other reason. Of course, if the buyer is really determined to categorically terminate the transaction and agree to return the property purchased by him, then this is his right, with good reasons. But our situation is different: the buyer does not want to give housing back, does not want to transfer money under the certificate of "parent capital",Yes, and the rationale for that can not give.
How to avoid a similar situation? There are two ways:
1) Contact the pension fund at the place of registration of the certificate for "maternity capital" and consult about the imposition of encumbrances on the property to be sold before the moment funds are credited to your bank account. There were cases when the pension fund refused to transfer money under a certificate if this condition was provided in the contract.
FZ of 1997 N 122-FZ encumbrance (or restriction) means the presence of legal conditions that do not allow to fully exercise their rights to the property.
2) You can negotiate with the buyer about taking a loan to buy real estate in a bank under the certificate of "maternity capital", than protect yourself from unnecessary worries about the integrity of buyers.
There are not many such buyers, but they are there. If you are already in such a situation - welcome to the court! The matter is long, troublesome, and even in the decision of the court in your favor will have to spend a lot of strength and nerves until the moment when you get the rest of the money for real estate.