Don't know where to start and don't want to drip feed, but trying to keep it simple...
DSS (11) has suddenly started texting DH & me & my DD (his stepsister) over the last couple of weeks. We were thrilled as usually there isn't any contact between contact visits.
Turns out that he has been 'smuggling' his phone into school and texting us from there. Ex is very angry about this. She says 'everyone knows' that mobiles give you brain cancer (although she has one, and so does her elder DS, and she insisted on her daily phonecall when we went on holiday this year even though we were using a mobile) and that DSS doesn't need to be in contact. She wants us to take DSS's mobile off him (DH bought it for him for his birthday).
Obviously, DSS is upset, and DH and I aren't sure what to do. He's allowed to have the phone in school (so long as it isn't out in lessons) and we have said that in Mum's house he has to follow her rules. He says he didn't lie to her, he asked if he could take the phone into school to take photos of a piece of work and then it just came to him that he could then text us. We aren't sure if this is true, TBH, but do feel that ex is being unreasonable.