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

Hi,
can I get the VOA (single entry for 5 days to Shenzhen) with a Switzerland 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?
Thank you for your answer in advance.
Stephan