My in law used to run grocery store, their cost was actually higher then price from Costco/Superstore etc .. (say Coke/Pespi etc)
Well, back to the 80's and even 90's they were doing OK, people were willing to pay more from grocery store .. not anymore .. when their cost keeps rising ..
What's happening in HK now is, the grocery story is selling stuff at lower prices than the big chains, so the big chains are not happy. It is likely that the big chains are pressuring the wholeseller/distributor to "do something about the grocery store" so that it won't/can't sell at prices lower than what the big chains are selling.
Resorting to tactics like that is clearly anti-competitive la.
If HK has competition / antitrust laws, there may well be a legal case on this.