You will never be able to actually see the uploaded letters, just that they are there and in your file when they are uploaded. My guess is that you can't check on anything much before September 1 when ERAS opens.
It is very likely if it has only been 2 weeks since you sent stuff to ECFMG that they haven't uploaded them yet. After all, they receive tens of thousands of documents and are only human...2 weeks would be hopeful, IMHO.
If you want to know what they have and what they don't, the best way is to call them, since they won't answer emails. However, calling ECFMG is very painful and expensive since you will be on hold for a considerable period of time.