Q: The course that I downloaded does not appear in the library (same movie downloaded twice but still I don't have it)

I have subscribed to course coding together (Stanford)

I have downloaded lecture 1 & 2 both movies appeared in the library but the first 10 minutes are kind of ruined. lecture 3 and 4 downloaded twice but I checked the library nothing is there and I have to download them again from scratch! and also I tried to download lecture 11 and after it is done (as shown in the picture) still I get nothing in the library!!! what could be the problem. please advise