First of all... Thats one short open letter... If you think she will trust you when you make a real open letter to her?

Regarding rhe time she needs to reply, when things are calm in forums, expect a fast reply. These days, there have been so much problems going on, they are working hard in the HQ, then don't expect a fast reply. Dont expect a reply at all.

Devs dont reply to all their messages on the spot and sometimes choose to just ignore them. They work by priority. So if your issue isnt very important they might reply later (and then they get more and more important PMs and your PM ends in the next page). If you don't get a reply, simply send it again with a more catchy realistic title... Not an XXXXXXsmall size open letter :/