Terrible Technical Support!

How in this day and age do you have an ISP not offering support after 5pm or on weekends? I called around 4pm today and was told that the tech support were all busy, so I gave my contact details and was told they would call back. At 4:30pm I called again and was told the same thing. Now, after 5pm you cannot call and their voicemail inbox is too full to leave a message. Fortunately for me the problem is not with my internet access but rather setting up my mobile data. So, I've had to resort to logging online and \EMAILING"their support department"