Voicemail issues

for many years now I have tried to deactivate my voicemail on my number. Even going into MTN shops, and spending many hours with the call services centrum on the phone just to be informed my number is too old and they can not remove the Voicemail option. In the day and age where we at it seems like a very weak excuse. also in today's age where one has a choice why is my choice been taken away from me.