DSTV wants me to pay for days they failed to disconnect

I received an sms that I will receive a discount of R110 and pay R299 on my account with no reconnection fee. DSTV wotsapp said I must pay R454.07 as of yesterday. Today when I phone the contact centre, the amount I need to pay is even more with R95 that they explain as grace period. My decoder always reflect that if I do not pay before the 2nd my account will be reconnected. We stopped using TV or DSTV services mid March because we were renovating and I expected DSTV to disconnect their services on the 2nd as they always promise. To my surprise when I want to reconnect they tell me I owe R95 for grace days. That is not on, I cannot be paying for someone who did not do their job and disconnect my services on the 2nd of May when they were supposed to. Please do not rip me off at daylight. This I will not entertain, please attend to it. I will take further steps because you can never charge me for failing to do what you needed to do - disconnect.