Can we use the 72 hour if our regular travel visa was rejected?

Hi 😊 We are a couple from Denmark( one of the 53 countries)
Our travel entry permit for China was rejected.
Can we still use the 72 hour transfer rule?
We fly from: Chiang Mai ( Thailand) - Beijing and from Beijing two days later to Doha.
We have no criminal record, we have a print of our bank accounts, we have the address of the hotel we are staying at in Beijing, and of course the flight tickets.
I dont know why we got rejected for the regular travel L, maybe because we arent married? Or maybe because we asked them to send the entry permit to a hostel address in Thailand ( because we were not at our home address)

And one other question: If they reject us the 72 hour transfer policy, can we just stay at the airport for 2 days or are we sent back ?

Best regards
Sonja