Q: Apple music trial

You should not have been charged for the free trial.

Help here >  https://www.apple.com/asia/support/music/contact.html

You were charged for the free trial because they automatically sign you up for automatic renewal. So when your Apple Music trial expired, they continued the service and charged you for it. You can stop it by going to Settings > iTunes & App Store > Apple ID: >View Apple ID  and then under Subscriptions, tap Manage. You can stop automatic renewal and cancel your subscription there.

To avoid this in the future, turn off automatic renewal as explained before your Apple Music trial ends.

If you signed up in early April, your 3 months free trial is up, and as clearly stated in the Terms of Service unless you turn off Auto Renewal, it will automatically renew and charge you monthly after the first 3 free months.

Nothing odd about it.

You can turn off Auto Renewal and stop the charges, but lose access to Apple Music after the month that has already been charged is over.

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