Evey Odd Page Displaying White Text

So I got a PDF document from store recently and was able to read it fine for a few months but all of a sudden when I open the document ever other page has white text rather than black which it didn't have previously. This makes it impossible to easily read with the white background. I'm wondering what caused this and how I can change it back. I know it's not a problem with the PDF itself because I got a new copy from the writer and he confirmed it worked. So I'm a bit at a loss. Does anyone have any tips? I don't have pro or any other editors but this shouldn't be that difficult. I've included a picture below to give and example of whats going on.