Disappointed by Achermans

I have been paying my Achermans account via eft, because they've been sending me letters on how I can pay my account through other of their channels. I paid via eft for 6 months, on the 7th months I received a call from vvm something, and they said Achermans has handed me over to them, I asked them how, because I've been paying via eft? The answer I got from them is that they don't know. I went to 1 of Achermans shop to find out what's happening, I was told to send the proof of payments, and it was last year around October. I waited till this year, went back again and it was the same story, send us your proof of payments and will take it from there. My question is why would they send us those letters on how we can use those channels, but our money doesn't reflect in their books? I'm very disappointed by Achermans.