Is it permissible to purchase a phone that was offered for sale by individuals who bought it through monthly contracts with mobile telecommunications companies, then sold it before fully paying its price and fled the country?

It is permissible for someone who has bought phones from companies in installments to sell them and dispose of them, unless the company stipulates that they should not be sold until all installments are paid. This falls under the category of pawning the sold item for its price, which is permissible according to some scholars and the Islamic Fiqh Council. However, if the sale is done without the companies' knowledge and the seller wishes to get rid of the remaining installments, then it is not permissible to buy these phones from them, as this would lead to the loss of the companies' rights.