Mtn Fibre

I signed up for the MTN Fibre for R269.99 month to month meaning I pay a month in advance my first payment was R538 which means I paid for the pro rata and a month in advance which was September and October. I kept money in the account to pay which was close to R300 the debit order did not go through stating as insufficient funds. I called their call center and i was told that I had to pay R480 when I asked how that was calculated the agent Somila Nfanase did not give me a coherent answer. I was also told that according to their records there is no payment from my side even the one I made for R538. It has been 2 days I was told the matter will be sorted but no luck. Lines are not going through no response on Facebook either