VOA (single entry for 5 days to Shenzhen) for Indian passport holders

Hi, can I get the VOA (single entry for 5 days to Shenzhen) with a Indian passport? Can I get it in advance? (for example apply for the VOA on Sunday and crossing the border on Monday?) What will be the costs? Do I need an invitation letter from a Chinese company or a Chinese person?
Pravin Buty