Now i am not sure about Hong Kong law but in some countries exist an international archive that states if you are a bad user of credit/debit instruments (Europe, Asia, North and Central America, and Oceania). Now if the Hotellier find out that you have tried to contest the payment he got 3 options: 1st loose the credit, 2nd contact the bank (for free) and give explanations (takes a lot of time), 3rd contacting the national archive and paying a fee for official comunications to the autorities and even showing the "contract"(this is the evil path and is even the less known). You have "signed" a contract with `booking.com` and they did with the hotellier, the hotellier has the right, in case you use an instrument like the debit card without the plafond, to ask this international archives to place your name on them, and now the bad news, what does imply? The Bank is obliged to prevent you from using any of those instruments from 6 months up to 5 yrs. At this point I'll say I will be happy to pay the fee needed.