The QTS website shows two addresses. The actual website (jade.com hk) doesn't seem to be working.
G/F, Richmake Commercial Building, 198 Queen's Road Central, Central, Hong Kong Tel: 25439168
4/F, Tung Hip Commercial Building, 248 Des Voeux Road Central, Sheung Wan, Hong Kong Tel: 28512686
https://www.qtsa.com/en/qtsa_members...=detail&id=393