Zone updates on cellphone

My mum is a pensioner. Since about two weeks ago she keeps getting zone updates on her phone. I have, personally, phoned the call centre from her cell phone 3 times. Every time they have assured me they will cancel this service on her number. We had to switch off the phone for 10 minutes. Yet still we are receiving these. Constantly, all day. Why cant the call centre deactivate this service!

Surely it cannot be this difficult.

Please assist urgently.

Thanks