This is a rather strange situation. There is no clear answer to it.
1. There is a culture difference in Asia vs. Western world. Privacy is less defined in the East. So this is not uncommon. Culturally, this practice is accepted.
2. It is not unusual for friends and family to call hotel and try to find the guest. They may not know the exact room number. Some friendly hotel rep will find them for you. Thank you very much!
It is going to take a long time to educate the hotel operator to respect the more "Western" privacy. But it takes a long time.
The best way for the OP is to go under the radar. First, solve your own personal problem, the root cause. Second, stay at a hotel that the intruder would not know. There are plenty hotels in that large city and the intruder can't call all hotels to dig up the name. You can tell hotel operator for the "absolute privacy". But you know some staff may not follow the instructions.