Downgrading Issues - causing stress to the elderly!

My grandparents are in their 80s and needed assistance with downgrading their DSTV package due to financial reasons, their debit order date being the 2nd of each month. On 2nd November my grandad and I called DSTV to downgrade so the lady said the debit order already went off so she will schedule downgrade for the next month so I said ok. On the 30th November I called back to ensure they do the downgrade so the lady said the changes where not made on the system by the previous lady so again we had to make the changes. The total reduced from R889 to R500 - the lady ensured me that the debit order amount will change from R889 to R500 on 2nd December. So anyways on the 2 December the DSTV channel package changed but then when my grandad checked his statement they still debited the account with R889. He was very stressed out because he cannot afford this. When we called again today for a refund of the difference, the next lady on the phone tried to cover up and say or that it was a system error, then I said well you downgraded the package but still charged us the R889 so please refund the difference or let me speak to a manager. She put me on hold for a very long time - then she said it was DSTV mistake, a system error but she can cancel the debit order from January where we can pay cash going forward and also she can only downgrade us on the 2nd January because they can only do downgrades on the 2nd of each month. This is complete nonsense - firstly the package was downgraded so all you have to do is refund us the difference, since we called in many times and the mistake is on your side. So i told the lady, I will be complaining about this. DSTV please contact me and sort the issue. I am complaining here so that you can wake up and stop causing your loyal customers unnecessary stress. My grandad is in his 80s, he does not need this nonsense and stress - please refund his money. In fact no customer needs this nonsense. I will be writing this complaint both on hello peter and also possibly on social media - until you decide to better your customer services and I am eagerly awaiting your response and I again request an immediate refund , or a credit of the difference in amount which can be used for January subscription. When people decide to upgrade then you quick to increase their debit order amount but when they need to downgrade, (especially in these difficult times) then you don't want to reduce their debit order amount - no fair.