Lack of urgency and assistance on the ***** helpline

Someone tried/ succeeded to hack my number by changing the details. I called MTN customer service to assist and a person named lindah (guy) answered and in summary refused to help saying I'm not the acc holder. I explained my father was the acc holder (provided all details to justify) and simply requested that he freeze (not change anything just freeze) any changes made to that acc for the safety of the info linked to the acc till my father can call the helpline. He still refused to do that. Acc has had the same details for over 20yrs what are the odds that there'll be changes and if there are who made the changes since it was neither for a fact me nor my dad. This is horrible service for a ***** case and lack of urgency from the helpline.