As a general rule (and not just in English), when a word or phrase is used as a close modifier in a complex noun phrase, it is stripped of its grammatical endings. (In German, for example the whole phrase is usually written as a single word, and only the last takes any grammatical endings). The way this appears in English is that usually a noun used to modify a noun stays in the singular, so
communication technology services
would be the 'unmarked' or basic form.
However there are plenty of examples of using plural modifiers, to particular emphasis. So technologies services would be emphasising that the service related to several different technologies, and furthermore indicating that by technology we mean something that may be pluralised: a technology in the sense of a particular collection of approaches and methods. Technology services would not be specific about whether it had this meaning or not, but I think would tend to imply that we are using technology in a more general, (uncountable) sense of "current equipment and how to use it" or something like that.
Communications is a bit harder, because that (in the plural form) is often used as the name of a field, like physics, and when used in that way, is usually singular. I think communications techology is much more likely than communication technology.