Q: how can i check what is on my cloud if i cannot use my phone?

You can use a computer and log on to https://www.icloud.com/ to see synched information such as Contacts, Calendars, etc.

You will not be able to view contents of a backup to iCloud (you can only use an iCloud backup to do a full restore to an iOS device) but you can verify that a backup exists. See the following for information: Manage your iCloud storage - Apple Support

If you were using Photo Stream, note that it is designed as a sharing/transfer method, not a backup. See the following from My Photo Stream FAQ - Apple Support

Hopefully you had iCloud backup also turned on. If you did, it should have been backing up automatically while you were charging your phone if it was connected to wi-fi. You would not see those photos in the Photos app at iCloud.com.  The backup contents are not viewable. See iCloud: iCloud storage and backup overview

Does using My Photo Stream substitute for using iCloud Backup or iTunes to back up my photos?

No. Photos in My Photo Stream are saved on the iCloud server for 30 days. To save or back up these photos, you must save them from My Photo Stream to your iOS device. Select the photos and choose Share > Save Image. You can then back up your photos using iCloud or iTunes.