Premium Increase

Good day, My monthly premium increased by R350 with no communication regarding the increase. I have tried to call the call centre but unable to speak to a consultant. I have send an email in which my personal details was requested via email and I am not comfortable to provide this over an email. They called me once of which I missed the call. There after they send an email not trying to get a hold of me. I responded to the email that I am available and that I missed the call. They refuse to contact me as they want my personal details. The after sales service is of a poor standard. Nandi Xabanisa did not bother to call again as I would like to know why my premium increased as I cannot see it on the statement on the App. Also early this year my premium increased due to inflation which was a first for me as this has never happened in over a decade that I have been a customer with MTN. Hope you can assist.