I would suggest that you scan a copy of the documents you sent them, and submit via case specific inquiry online. In the body of that letter you may provide the courier numbers etc. These case specific requests are automatically issued a reference number and there is no way that they wont get it. As soon as you submit it, you will get an automated confirmation email that you can use later as a proof in case needed. I tried this method once and it worked. When i sent scanned copy, they added that to my file. upon receiving the originals after a few days, they made a note on my file that they did receive and have seen the originals. After that they even sent my originals back to me. ( I found out all this through my GCMS notes).
