In Texas. Took a trip to Disney World in Orlando, FL with my girlfriend, my daughter and her son. With day 1 being the day of arrival, on the morning of day 2 she became unreasonably unhinged and texted me a screenshot of things she had paid for up until that point (resort reservation, tickets, rental car, ice cream and dinner which I had paid for) demanding that I pay her half immediately which I fully intended to pay half, I just anticipated that we'd tally up expenses after the trip and settle then. She somehow managed to miscalculate that by almost $1,000. Without giving me an opportunity to review it, she began to get physical and grabbed me by the arm so in order to deescalate I just gave in to her demand and paid her on the spot.

She broke up with me upon return from the trip. I later determined that she still owed me a little over $1,000 mostly due to that miscalculation. When I tried asking for her to pay me back and pointed out the error in her screenshot, she became extremely hostile and made up lies that can easily be disproven.

She then accused me of still owing her money and that "I'll send my guy to ask for it". She is demanding that I send her "itemized receipts" for anything I was asking for her to reimburse me for which I didn't keep any of the physical receipts and she knows that. She only provided me with receipts for the resort and hotel, nothing else. I provided her with copies of my credit card statements showing everything I paid but she still demands receipts.

I'm ready to just take her to small claims court. Should I send a certified letter first outlining what she owes me and why along with a reasonable no later than date and method for sending payment before filing with the court? Any other suggestions?