Poor customer service/details update

Just for me to have my numbers updated on their systems has taken over 3 months which still even to date their system still carries cell numbers to a Sim I do not have access to. I've attempted so many times to get this done by calling them and I get told someone will call me to finalise the process. I have not received any call from them when I call back I get told to be patient there has been a backlog, but then again for 3 months, just to update cellphone numbers?