Unhappy wit ackermans

I was walking in the mall the beginning of September, when a guy stopped me to open an account with ackermans. I did not want to do it, but he kept on, so I did it. Then I had to buy something to activate the account and I bought a sweet for R 17.95. The beginning of October I went to pay in store, have not received an accout. The que was quite long, as it was the beginning of a month, and the people was shopping. Only 2 cashiers was helping. I asked if there are not more cashiers, am still waiting for an answer. As I am not young anymore, I decided to go and maybe they will send me an accout. I received a sms without details and then an email accout. I was surprized to see the R17.95 was now more or less R30.00. I decided to do an EFT payment of R17.95 for what I bought. And still the sms's keep on. I send them an email, telling what I bought and what I paid, and that I am not going to pay their admin fees. They responded by sayng I must pay my account. I again rep**** that I paid what I bought and that they must close my account. Needless to say, no answer, BUT a few weeks later the sms's started pouring in. I phoned the accounts dept and again told my story, and she said I MUST pay, now it is R40.00 ... for a sweet of R17.95. They have not acknowledged my payment. I refused and said I won't pay. What bothers me, is all this time spending to send me sms's, and not 1 email again with no indication on an accout what this R40.00 is for, but I must pay. Now I received a threat. Is this really how they do business? They are badgering me now ...