MTN Billing Department

MTN billing department is pathetic, My normal debit order is R2420.55. On the 29 December 2020 they took R4632.23, and when I inquire they claimed that they changing their billing system, but promised to credit me with my R2214.68 within 72 hours. On the 30th they took again R2420.55 again I called and was given different ref number. On top of that, I have an outstanding reference number since 2008 for an amount of R742 still not resolved.