Is it permissible to buy a mobile device and sell it before taking possession of it, knowing that the buyer may be a shop or a friend, and there is a prior agreement with the owner of the first device that the sale can be canceled?

The question comprises two matters:

1. The ruling on buying and selling over the phone: The contract is valid if the item sold is described in a way that removes ambiguity, and the buyer has the right to return the item if a defect is found that contradicts the agreed-upon description. 2. Selling purchased devices before taking possession of them: It is not permissible to sell something before possessing it. However, goods can be sold in dhimmah (a contractual obligation) with a description that removes ambiguity, provided the price is paid at the contracting session (forward selling or bay' al-salam). Alternatively, the matter can be a promise to buy and sell, as a promise is not binding, unlike a contract.