Is it valid to conduct a sale without the presence of the money or the merchandise, as in the case of paying for a phone repair after its completion, knowing that the payment and the receipt did not occur at the time of the agreement?

Immediate possession of the price or the object of sale is not a condition in a sale, except in a salam sale where handing over the price at the contracting session is a condition, and in sales of usurious items where possession of both عوض (counter-values) at the contracting session is a condition. As for the sale of an object absent from the contracting session, handing over the price at that time is not obligatory. Combining ijarah (leasing) and bay’ (selling) in one contract is permissible according to the majority of scholars.