Buying train tickets at Hong Hom to Beijing

Hi there,

We are planning to travel from Hong Hom to Beijing on the 11th of August, is it possible to physically buy tickets at the train station at on the 09th of August in the evening at 1930 - 20h00 to be more specific on time? I could not buy them online, as the system or Mastercard could not accept my online purchasing.

Please can you supply me with sufficient information to be able to make a decision. Thank you.

Regards,
Pearl