I have travelled to Shenzhen twice last year and obtained my VOA at Shenzhen International Airport.

There is an office with a big sign just before immigration. Both times I have gotten a 72 hours free transit. As I was doing business in Shenzhen, this was all I needed.
Two weeks ago I was travelling to China and the airline, same one as I used before, denied me boarding of aircraft without a visa. They would not believe me that I could get the VOA at the airport. Has something changed? Is there somewhere I can find out this information. If it is still possible, I might be able to get a refund of the lost air ticket.