Changing services....**** I can't wait for a service rep and be on hold for so long ****

Any suggestions to help me out....I have to change some of our services but don't want to cancel everything we have with Comcast and the wait has been long and I unfortunately work nights, so I'm not always awake to be on the phone during the day and the call back time doesn't always work out for me.  I've tried completing the task online, but it won't let me and says there are no chat agents available.  Any help would be appreciated!   Thanks!