Handed over by Vodacom

I returned a Tablet to Vodacom with-in the 7 days cut-off period as per their contract in June 2016. Vodacom then deducted money from my bank account October, November, December 2016 and January 2017. I instructed the bank to stop paying Vodacom. I then received a Final Demand 1 August 2017 for R 2 243.75. I then called Vodacom 16 August 2017, eventually getting through to Thato Hleli who confirmed Tablet received in stock June 2016 (Cancellation and Stock returned) Reference Number 1-***0 691 had been created. 19 November 2018 I get an e-mail from VVM (VAN DE VENTER, MOJAPELO (PTY) LTD) (Tracers???), I quote; "We wish to inform you that there has been an information update of your profile at CPB CREDIT BUREAU, etc. and I I must call them to get assistance. To say the least I was a bit shocked! I went to see my lawyer. 5 December 2018 at 08H03 I get a call from VVM offering me a discount to R 1000.00 . Not we are sorry or we made a mistake? They owe me Money, I owe them nothing. NOW VVM does not respond to e-mails or calls. What am I to do?Disgusting behavior VODACOM!