Error reading stream on purchased download PDF

Is there a way to repair a purchased download, or do I need to seek assistance from the vendor?
I paid for and downloaded an 68.2MB document of sheet music, and when opening and paging through the first few pages, got the "There was an error while reading a stream" message. There are now blank pages throughout the document, including the two specific songs I was hoping to learn. I downloade it again, and got the same error when reaching the same page (3 or 4 of the document). The document is too large to attach here, unfortunately. Thanks in advance for any assistance on this.