As with factor 30. However, in letting both teachers know that this has happened and that you. as one of their supporters, feel aggrieved at sproglet being dealt with thusly, you need to remember that to save face one or other or both may lie. It never happened. Sproglet got wrong idea. If you have anyhting written down that says she should move to next level, worth taking along and showing them.
In mitigation, perhaps T2 said her piece jokingly and did not think of its impact. Also, have other kids been mithering to go up a level and have these little rotters told porkies / attempted the good old game of playing off Miss1 against Miss2? If so, while your child is not telling whoppers, it's difficult in the thick of it to tell one from t'other.