Schwab brokerage firm did not sell my stock by specified lots as I instructed and now I have a six-figure tax burden

Location: Pennsylvania, USA

Hi, TIA for any advice. Essentially, I instructed Schwab to sell stock in my taxable brokerage account by specified lots using a limit order. I changed the limit price using the Thinkorswim platform, and I was told by a Schwab representative, that by doing so, the order was changed from specified lots to FIFO. I now have a six-figure tax burden as a result. There's no indication on the ToS platform that by changing the limit price via ToS, that the stock would be changed to a FIFO sale. Unfortunately, the sale has already settled.

Do I have any legal recourse? Appreciate any advice you may have.