Unable to change surname past 13 years at vodacom

I am unable to change my surname for the past 13 years. I went in store they cannot change it, we emailed my marriage certificate from the store 3 times, I emailed my marriage certificate to client/customer services the email address that vodacom gave me in store. I have been calling vodacom. Its still to date not changed. This is absolutely ridiculous and wonder how this cannot be changed?????