URGENT: Deportation on my visa, I overstayed stupidly by 2.5 months.

Once I realized my mistake I quickly went to the PSB and they told me I had a series of things I needed to do. I did them and paid the big fine of 10,000 rmb and got an exit visa with a deportation stamp/sticker on it saying I had to leave in 7 days. I heard many who got back in from HK, but they denied me there and told me I had to go back to my home country to re-apply. I was sure I could get back in and was quite unprepared to fly back home to Canada.

Why was I deported while I read some aren't? I was on business visa for 2 years and prior had tourist L type. I didn't travel back to home country of Canada since I came in. Was this why deportation? not sure.
I am really wanting to get back into China and will get a job and Z type entry. But wondering will I be denied after waiting for all the paperwork to get done? Am I forbidden to enter again? Is there a wait period?
Can anyone help? Thanks!