What is the ruling on congregational prayer in the office, knowing that delaying the prayer to pray in the mosque leads to the departure of donors, and that praying in the office prevents some employees from shopping during official working hours?

It is permissible to perform prayer outside the mosque according to the majority of scholars. The proof for this is the saying of the Prophet, peace and blessings be upon him: "If you have prayed in your dwellings, then you come to a congregational mosque, pray with them, for it will be a supererogatory prayer for you." The Prophet, peace and blessings be upon him, affirmed the action of the two Companions who prayed in their dwellings, and he commanded them to pray with the congregation if they came upon it, by way of recommendation, not obligation. It is better to maintain congregational prayer in the mosque to attain its reward and the virtue of the place.