no criminal record question

I want to get no criminal record from Shenzhen police but was told I needed to be present there to get my finger print. I had no plan of going back at this time and wonder if anybody could help me with any information.

Also, when I left I did not do anything to my HuKou. Since I was told this was necessary to the completion of the no-criminal record, I need information on how to retrieve it (I left four years ago so I suppose nobody could find it any more?)

Thanks a million!