Wayne, as said above she's naffed her own rugs up, chucking all that other stuff on it.
The words "had a go at it" from a customer should set off alarm bells!
Your cleaning wasn't "patchy" was it? Unless you applied your pre-spray by pouring it from a cup..... or spraying it from a can?
Leave her with her problem that she's created, it's not yours!
If she's very unhappy just refund her money and use it as an experience to learn how not to end up taking on duff jobs in the future
(alternative answer: saturate and power wash but wouldn't recommend practising on an already angry customer's rug)