Unjustifiable payment demand harassment

I paid my account on the 6th of this month, and to date, I am harassed daily to make payment. The installment due was less than R180 and I paid R200. I do not understand how the Jet system operates. The account was paid at a Jet store, the payment should surely reflect immediately. This is not the first time this has occurred to me. Dumbos my credit profile is affected badly by this, sort out your systems.