Common courtesy and politeness cost nothing.
You are more likely to get a reply if you observe the small courtesies of life.
As far as I, and others, are concerned, "who owns H5 ATM" means "who owns H5 Automatic Teller Machine"
That is the common meaning of "ATM".
The purpose of language is to communicate, and anyone who uses a common abbreviation to mean something other than its normal meaning is not thinking clearly.
Anyone who queries a polite enquiry by telling the enquirer to "get a life" is just plain ignorant.
(For the benefit of anyone who may be ignorant, an Automatic Teller Machine (ATM) is that magic jigger in the wall that you put your card into to get money out - OK?)