I downloaded the InDesign 7 - Day trial and after 4 hours it told me my trial expired. Is there a way to fix this?
I don't think there is unless you have another computer that you can download the trial to again. Maddening!
I think you might be able to take out a monthly subscription and cancel within (I think) 14 days (check this).
Read the document Barb points to.
I'd bet in the majority of cases here's what happens: A person intends to try out a Creative Cloud application. In anticipation of this, they download the trial, but they don't have the time to test it out immediately. They wait a few days, then begin testing. The test version ends early. As the Help file points out, the trial begins WHEN YOU DOWNLOAD THE TRIAL.