Mindee left 2 months ago. They'd asked me before handing in notice if I could have her a couple of days over summer hols. Agreed, subject to me having space. Mum was sketchy about whether she would actually need me, dates, length of days needed etc. (same parent who didn't even say thank you for the 2 years I'd looked after her dd, sometimes til 8pm, often when I'm actually closed - I'm mean to be term time only). So, holiday flights have changed and I'm now away on the days she'd asked me about. I've txt her to say I'm no longer available and she's having a massive strop about how she'd booked me. Bearing in mind that she'd already been warned that if I took on other mindees I wouldn't be available, and the fact that I'm out of the country and she has a history of phoning me the night before to say she's found a cheaper option, how do I word my response?