Horrible service received!

I walked into Vodacom 2 weeks ago to update my banking details for the debit order running against my account. I also enquired what my total due amount was so that I could settle it. I was given a figure, which I paid immediately in the branch...2 days ago I walk into yet another branch to do a sim swop and I am advised that my account is in arrears! Obviously, this makes no sense as I had paid my account (in cash) just the other day, so my next payment will be debited monthend. I then call the customer care line and the agent checks "all their systems" and confirms that the total outstanding amounts on my account is R0.00 I requested her to cancel my contract but because she "resolved" my issue, I opted to upgrade instead after being offered yet another deal. This morning, I receive an email whereby I am now threatened with legal steps. What nonsense is this??? I have been a loyal Vodacom customer all my life, I'm utterly disgusted!