Colleague's wife is screaming at me on call.

Basically some of my work friends and I went to Thailand. We had a gala time there and explored a ton of places. All of us stayed at this really nice hotel which had a beautiful swimming pool. We went swimming there quite a few times. So, I have a DailyObjects bag that I got for free on my purchase. I use this primarily for carrying towel, undergarments, swimsuit, sunscreen etc. Another colleague of mine has the same bag with the same colour. He accidentally took my bag and I took his. I got to realise this when I opened the bag and saw swimming trunks and a book. I called to tell him about it and it was too late. His wife picked up the phone and enquired about why I had placed my undergarments in her husband's bag. I clarified that it is just a mistake and that we accidentally swapped our bags but she was not budging. So I hung up after getting scared. She has called me 5-6 times in the last week but I am too scared. What should I even do? Whenever I try to explain the situation she starts screaming at me again. It was a simple mistake but this woman is overreacting and my colleague also agrees. She's completely psycho and thinks that I am trying to steal her husband.