Frustrating lack of care and service

I am experiencing an issue with receiving some of my sms's, but not receiving others generated to verify my identity. This is causing all sorts of problems for me and after calling vodacom I was given a reference nr. I then received an sms telling me that they tried to call me but that they could not get hold of me and that the ticket is now closed. I never received a missed call from them. I have since tried twice to get hold of the backend staff to inform them that my issue has not been resolved and both times I was told that they cannot get hold of the backend guys, but that they will send them and e-mail and that they will follow up with me that I was contacted. Nothing happened. I do not know what to do anymore. The only thing I can think of is to change service providers. Vodacom does not seem interested to sort out customer problems and their customer care staff are completely useless. This is a highly frustrating situation. My account has been with them for over 20 years, but I guess I will have to move on.