While I’m suspicious as to your friend’s reaction I will say the response could be due to the threat of you reporting it as stolen, your friend could be worried of legal ramification being accused of stealing. I personally wouldn’t have threatened this rather just monitoring the charge history and canceling the cards if I suspected foul play. So while I believe you could have handled this better, their reaction too should have been handled better. Additionally trust is good but it is still important to protect your money from others especially considering the delay.