Can I Please Hold the Line?

I've been trying to get through to Citizenship and Immigration for three days! It doesn't let you hold the line, it disconnects if there are no available agents. I do know that they do not accept aggressive behaviour or language and that I may be warned that my call will be terminated if I choose to use such actions. i also know that my call may be recorded for quality assurances but if I choose not to have my call recorded I must inform them. Then I get about four bars of elevator music, three rings and another recording informing me that there are no agents and to try my call later and that their least busy days are Thursday and Friday. I tried so frequently today and yesterday. Why can't I just hold the line to ask my three questions?