DATA ACCOUNT OF ALMOST 10K

I received an account of almost 10K for data - this is on my daughter's phone, I have already requested a limit to be set twice, I check her phone on a weekly basis and she switches the data settings off when she is not using it. I have also bought additional data to ensure that the account is as low as possible. All apps not in use is either disabled or \force stopped"under settings. The call centre now tells me a limit cannot be set"