Mostly because Blizz customer service/helpdesk have nothing to do with bugs and unless they have a workaround/compensation authorised by the devs they cant really give any resolution until the issue is fixed and been signed off on.
Posting either in the in game bug reporting tool or in the bug report forum is as much as you need to do. The devs collect the info from that forum and work on a fix - fixes they will do as a collective not on an individual basis. They wont have a back and forth conversation tho unless they require more info.