I think I stole... HELP

I broke my I phone 6 so I was using my dads iPhone 5 until I could get money to fix it. My close friend gave me a life proof case that she didn't use anymore to put on my phone. My other friend wanted a life proof case so I let her use that one for a few days because my phone was fixed and I didn't need it anymore. It was broken before, and she wanted a new one. So we called life proof and told them that it was broken and gave them a different story as to how she got it and then they sent her a new case, even though the original wasn't actually hers or mine. Did we technically steal from them?  Could the person who gave it to me get in trouble because I used the original serial number? HELP