Bongo US Bongo International stole my check Internet, Connecticut

I had a mail forwarding account with Bongo US.   An item arrived from the Department of the Treasury.  I did not know at the time that this was a check.   I forward my mail in a batch as usual, but this item is not included - I contacted  BONGO and they did not know where it is....So how did it go missing from a sealed DHL envelope? Only if it never got put in in the first place..... Clearly someone in their firm stole the check.  Never use BONGO US - they will steal your mail!