Discovery wont pay back money owed

I cancelled my discovery over a year ago, I Owed them R2000 from my savings as I cancelled before year end and my svings were depleted. I made a payment plan with them. They still handed me over to lawyers who harass me daily. I have now paid R1000 more than I should have back (I was informed this by their accounts department) The awyers still harass me, I have emailed them all my proof of payments! To no avail! I have messaged Discovery on FB, nothing, I have called them, nothing. Been around 4 months of this now. I want my R1000 back and the lawyers gone thanks!!! So frustrating!!!!