Q: I am trying to cancel iTunes free trial. Apple's inst. don't apply why is this so hard?

It's impossible because there is no such thing as an iTunes free trial. What you likely mean is the Apple Music free trial.

View, change, or cancel your subscriptions

https://support.apple.com/en-us/HT202039

Sheila,

Assuming you are talking about Apple Music, it works a little differently than other subscriptions.  Also be aware that you are not canceling the subscription, you are canceling the automatic renewal.  You may still use it for free for 3 months if you wish. 

See details here:  Manage your Apple Music membership on your iPhone, iPad, iPod touch, Mac, or PC - Apple Support