Another point

The terms and conditions are only binding contract between the bank and the primary card holder.

They didn't send you the terms and conditions, did they?

Plus, the primary card holder along can activate all the additional cards. So the bank does not have any proof that you had agreed the terms and conditions, so you are not liable.

Another thing your can do is to help the bank to find your friend, even if he/she is in China, and thus relieve yourself from collecting agents.