The use of Third-party contact centers is a mess!!

Initially, I have tried by all means to get assistance from the contact center - but all that happens is that I get bounced from one department to another or I simply get placed on hold for up to 30 minutes or more resulting in me eventually hanging up out of frustration.

I have a sim-only contract with them which was due for an upgrade since May this year - and since then I have been harassed by what seems like third parties who are forever calling to offer me upgrade including devices. I had turned this down, but was recently in contact with the retentions team who offered me a very similar package to what I was on (a generous amount of data and fee minutes) along with the option to cancel with a month's notice should the need for a device.

After repeated calling and being bounced from one person to another I was told that I was misled into believing I spoke to "MTN Retentions" and was instead assisted by a third-party call center who probably captured the wrong plan. The individual I was then talking to said she can assist me with "another upgrade" that would be subject to another "upgrade fee". I really don't know how to cancel this because they fail to provide services but continue to charge you!!