I don't know all the answers to your questions, but I do know the Call Centre is hard to get a hold of. I sometimes have to call a dozen times to get through. Also, make sure you're using an actual phone and not Skype or another computer based calling program. They don't mesh well together.
Generally, that status means they have received your file, but haven't begun to process it yet. Did you include your UDI or Client ID # with the letter?
Also, if you have any proof of separation (separation agreement, restraining order, new lease in your name only) I would provide copies to Immigration as well so they know you're serious. Hell, if it was me, I'd have a book of evidence!
You may want to post in the Spouse Sponsorship thread stickied to the top of the Family Class section of the forum or make a new thread and call out for help from senior members. It can't hurt to ask around. The more knowledge you get, the better.