Poor "Security", no options provided for resolution, refusal to transfer

I am trying to cancel a contract but I keep getting told that I am failing my security questions even though I KNOW ALL MY DETAILS. My ID number allows the advisors to open my account and for me to view my statement I know my name (obviously!) and I even read it off my statement I provide my address as per my statement (an old address that I have not lived at for more than 6 years that has not been changed, even though I have asked many times for it to be updated but I provide this and my current address) I know my bank and the date deductions are taken as per my Cell C statement and bank statement I know my email address, it's where my statement gets sent to. So with all this information that pertains to my account and forms my security questions, I do not understand why I cannot access the account and close my contract. I have the concern that someone has **********ly accessed my account and perhaps changed my details which leads to my security failure. Still, no one wants to transfer me to the ***** department BECAUSE I CAN NOT PASS THE SECURITY QUESTIONS. How am I able to verify my details otherwise? I have spoken to 2 managers who were no use. I am not given any options to have my details confirmed correctly. I have sent 2 complaints via the app email. I have provided my payment due as per my statement which was queried as a further question and I still failed, even though I have the statement in front of me. I am being locked out of my own account and being charged for something that I am not being allowed to cancel.