If your movie only plays sound the problem is most likely because you picked the ProRes4444 file format during checkout. This is a professional file format and requires that QuickTime be installed on your computer.

QuickTime comes installed on every Mac. If you're on Windows you can download it for free here: https://support.apple.com/kb/DL837?locale=en_US

If you cannot install QuickTime on your computer contact support and ask that they re-render your movie in MP4 format.