iPhone no longer opening PDFs in emails

I used to have no trouble opening PDFs on my phone or computer.  Then I signed up for the free trial for premium services.  When I decided not to continue everything did not go back to the way it was.  I figured out how to get what I needed on my computer but my iPhone no longer opens PDFs sent thru email.  I've downloaded the app, restarted many times and still I can't open a single pdf attachment.  Errr.