Dstv price lock taking over paymnt from customers

I took a price lock the agent advise me it was R549 for 24 months, Dstv will start charging me from the day of the installation and the installer needs to cancel my residential dstv, on the 9th of July the installer came and they also called the dstv contact center n cancelled my old dstv. Fine, on the 27th i got a bank notifications that dstv deducted R 814. From my bank accound. And that was never the agreement. I send them a text on messeger there agent reply that im still paying for my old dstv and in August they will deduct R 958. I called the call center they told me my old dstv was not cancelled i told its not possible becouse the installer call in to cancel using my phone and i was present her name was Palesa , again this morning on messeger i was given a new excuse that i will pay R 615 i asked how becouse you already deducted R 814 and i want my refund for the over payment becouse my installment is R 549 now they change their story that "Price lock was activated on 09/07/2019 We couldn't charge you R 549 for only 18 days, that is why you were charged only R 371.80 for the period of 09/07 - 26/07 then on the 27th was charged R 399 for Dstv Compact service and Access fee of R 95 " what kind of nonsense is this i agreed on R 549 was never advised of pro rated fees or Access fees. I just need my refund and my installement to be the amount i agreed on R 549. If not please kindly come and collect your explora becouse im not s cent more than what ive agreed on.