It doesn’t matter whether your tone isn’t chill or it is, quite simply it’s not decent behaviour to not pay back someone after they bailed you out of a tough spot. Tone observation seems like a distraction she’s thrown in from the side.

I don’t know what is going on but it’s possible this woman is picking fault with you to justify her own poor behaviour. It sounds like you’re alert to this, and good you are, I wouldn’t recommend staying in touch.