I don't understand understand- you mean you overstayed in China 3 days after your visa expired, then got a new one in Hong Kong?
I do have another Guangdong visa related question for all- I have just been told that even if you're coming and going on the SAME visa, you still need to re-register at your local PSB every time you leave the country! Is this true? I have been living in places along the PRD for almost 4 years now and this is the first I've heard of it. I did go back to Oz for Christmas and never went to reregister, obviously on the same visa, and I'm actually out of the country again now.