Is it permissible to work in developing and installing telecommunication services such as mobile internet, email services, and the exchange of photos and videos, knowing that these services may be used for both permissible and impermissible purposes, and that the responsibility for monitoring their use falls upon telecommunications companies after installation and testing are complete?

The default ruling is that it is permissible to produce, sell, and deal in these services, unless it is known or highly probable that they will be used for something forbidden, in which case it becomes prohibited. It is difficult to know the type of users, and as long as your work is far from direct interaction, the ruling remains based on the principle of permissibility. The sin of the transgression falls upon the perpetrator, not on you.