getting call log

The best source is your cellular bill. You can probably view it and print it in your account on your carrier's website. The "Recents" on the phone itself may not have enough information to satisfy a legal request, but the bill should.

Recents will only get you so far. If you need more than Recents, contact your provider and they should be able to furnish a log for the time period you need.

In your phone application, tap recents at the bottom.