Of course she's taking the pee.
If she was genuinely upset at your work, why would she want you to continue it?
I just couldn't stay and finish after that, I think you've done well.
I had a customer agree to a written estimate for changing a ceiling light fitting for £30.
Come in, set up dust sheet, ladders and start taking down the light fitting.
Then she comes in and says my mate down the road says he can change 2 light fittings for £30.
After she had left the room, I put everything back as it was.
As I was leaving, I told her to get her mate to do it for her.
Her face was a picture!