Only in PRC on IP squatters . Just checked the CR site - from their guideline Pg 7:
Any objection to company names should be submitted to the Registrar, giving reasons in full and including any available evidence of confusion which is claimed to have arisen. Objections should be headed “Names Complaints” and sent to the New Companies Section of the Companies Registry on the 14th Floor, Queensway Government Offices, 66 Queensway, Hong Kong
No prescribed format for objection letter, you can send it, doesn't need to be from law firm but getting them involved now is wise move. I hope it's still within the 12 mth period.
Name/CR aside, do a search on ipd.gov.hk to see if your [XXX YYY] is registered as a trademark in HK (assuming you didn't register TM for yourself before). If it is actually registered by someone else, it's a different problem. But if it's not registered, I think you need to do it asap for your company in HK (and PRC or other place if you have dealings there). I'm assuming they're using such a similar name on purpose but even if it's not malicious, now that you know there's someone who likes using the same name and in same business, you need get the TM right otherwise it'll be a pain once they get it.