Nightmare red tape service. Will keep shedding customers

Worst experience of all companies I dealt with. I bought a sealed phone off Gumtree which had a clean imei at purchase date. Few months later, vodacom blacklists it. I wrote a long letter detailing the event with emails, I'd etc. No feedback other than a case number for almost 3 months. No one can tell me why it's blacklisted or who deals with it. Blacklisting puts me to ***** who says it's not a ***** case and so this circus goes on. I heard Vodacom service was terrible, but my experience was even worse. I don't know whose in charge there but they lack proper processes and Controls and will lose me as a customer for life. I get better service at the Dept of Home Affairs.