Getting some documentation on how the Sales Center, Call Center and Customer Portal all work together is on the to-do list and we should have something put together shortly. It's totally understandable that you aren't too sure where to start. In the mean time though, if there is anything I can answer for you that really just doesn't make sense, ask away!
As for the issue with deleting, I was able to get a similar issue to duplicate on my end. Let me look into it and get back to you.