What's worrying me is that whoever sent them addressed her by name.
She only has a few names in her address book (all of whom I know well) and only uses the phone occasionally, if she's going to be out for the day with another family/friends and might need to call me.
How could anyone have got hold of her mobile phone number (which she doesn't even know off by heart and has certainly NEVER entered in a children's website or similar), and how would they have discovered her name?
I think I'll contact the police tomorrow, and I'm sure they will advise me to change the SIM card/number.
The 'number' for the 'caller' is not a normal number; it's only a few digits long and the text comes up unusually small.
Has anyone else's child experienced this?