Harrasment for a account that was paid in advance for a full year.

I am being harassed by DSTV accounts, I paid them R6919 in full on the 25th March 2021 for the full year till March 2022. My April 2021 statement says ZERO balance . As I am typing this review I am on hold with DSTV with my 2nd call ,25min long, the accounts manager refused to take my call, the excuse the second lady gave me was " due to covid regulations they can not share a head set" What happened to the good old way of transferring call to the manager ? I have my latest statement on the DSTV app, this one says I am in credit of R 55. In March 2021 , as I do every year, I go to the site, see what is due for the year April 2021 to March the following year. I paid what was quoted, how can a years subscription suddenly change a few months after I have made FULL payment ? No wonder DSTV is loosing customers to Netflix and Brit box, they cant even get their accounting system to work. I will be happy to receive a refund from DSTV for the months I have paid in advance, Nov to March 2022. I have sent a few emails to the accounts department, never get a reply, I have told the debt collectors from DSTV my statement says Zero and the account was paid in March in full. I wonder if this review will trigger a manager , not a accounts clerk to call me back. I am so glad all their calls are recorded ...I hope the manger listens to all my calls. George Fairfull