My Abusive Ex Stole Credit Card

I left my abusive ex on October 30, 2018. Over one year later it seems that I am still being affected by her. While I was with her, she apparently took one my credit cards (Best Buy) out of my wallet and used it to make a few sizable purchases in which she never made any of the monthly payments on. I was unaware that these were made because I never used the card. I opened it, and made one purchase, paid it off, and then it was a dormant card. Fast forward till now, all of my mail has caught up to my address change and I have received a court summons for a civil lawsuit for the charges unpaid on the card. I received the summons on November 25th, 2019 and sought legal counsel and after presenting everything that I had to a lawyer, he determined that my best bet was to pay the debt and then sue my ex afterwards. This leaves me in a bind and I cannot afford this on my own right now within the time frame. The amount that I need is 1713.04 and possible the interest afterwards/incurred + court costs.