In her email to you she says, "I am not emailing you for sympathy" that could be taken as a threat but I don't take it as such. (yet) Because: she then says, "I just thought you might appreciate knowing what happened, as I imagine it will happen again to other customers of yours." While it is possible, I wouldn't automatically assume that this is someone who is after money. I think that in this particular case I would try to work with this lady. When she says, "causing damage that cannot be rectified" maybe she is saying that since according to their terms - it cannot be set right, then they don't expect it to be set right. Up to this point she hasn't asked for anything except for your comments. I believe that if I were going to "put the ball back in their court" (which I think is a good idea, btw) I would do so with kindness and warm courtesy for now. If in fact she is fishing, that will come out soon enough. So, when I responded to her I might use phrases like "you had this experience" rather than "my candle blew up". Also I agree with Bella Luna, especially the last paragraph.