Ex-friend has been purchasing Lyft rides with my card on their app for months

I have been going over my finances, and found a bunch of Lyft charges on my account activity, dating back to April of 2016. I do not have a Lyft account registered to my phone number, nor have I installed the app on my phone as I only use Uber on occasion. After further investigating, I remembered that an ex-friend of mine inputted my card information one night to use her Lyft app. The next day, I sent a text to her to remember to remove my card as the default payment method on the app. She replied back, confirming that she received my request, and I thought the deed was done. Months later, I just found out that she never took my instructions and have been fraudulently using my card to sneak rides without me noticing. She lives in downtown Seattle, so the rides were often such small amounts that I wasn't noticing the small dings on my account. In accumulation, she has now spent hundreds of my money to pay for Lyft rides that I did not authorize.

Before I realized who/how these charges were taking place, my credit union gracefully credited me back money for the Lyft charges they found just for the last month, and I have since gotten a new card issued to me. However, I have to turn in fraudulent paperwork consisting of all the charges dating back to April. I am going to complete the fraudulent documentation consisting of all the charges taken place AFTER the initial one I offered to pay for. What are my legal grounds here? Is this something that people can get away with by using Lyft? Has anyone been through this situation that can elaborate? Is there a possibility that this can bite me in the ass somehow because I authorized the first charge? I feel extremely taken advantage of and I have completely cut her out of my life. But I need to know the correct way to go about this legally.