If a person is indisputably owed money and the debtor has not paid him, is he entitled to enter the debtor's store or home, and take merchandise equal to the value of the owed sum in lieu of payment?
The Shulhan Aruch (Hoshen Mishpat 97) forbids seizing a debtor's property in lieu of payment, for two reasons. Firstly, Halacha forbids trespassing on somebody else's property, and this prohibition applies even to the property of somebody who owes the trespasser money. Secondly, when objects – as opposed to cash – are given as payment for a debt, they must first be assessed by evaluators assigned by the Bet Din (Rabbinical Court) (siman 101:9). A person may therefore not seize a debtor's possessions independently, as the precise value of those possessions must first be formally established before they can be used to repay the debt. He must make a claim in a Bet Din, rather than take the law into his own hands.
This Halacha applies only to cases of owed money. If a person is owed a particular object, such as in a case of a thief who stole an item, then Halacha indeed allows the victim to seize the object in question, provided that he is certain beyond a doubt that the object he seizes belongs to him. Since no evaluation is necessary in such a case, it is within the individual's right to independently seize the object he is owed, without first appealing to a Bet Din.
Summary: A person who is owed money may not seize the debtor's possessions in lieu of payment; he must make a claim in Bet Din. If a person is owed a particular object, then he may seize the object on his own, without consulting with a Bet Din, provided that he is certain beyond doubt that the item he seizes is owed to him.
See the book- "Pure Money" by Dayan Cohen, pages 209-210.