Pathetic service by Vodacom

In mid December 2019 I requested a pre cancelation quote to pay and finish my cellphone contract with vodacom. I paid it in full as per the quote and was informed after that by 3 consultants (of which the calls were recorded) that I owe nothing on that number which is now a pre paid. On the last day of December Vodacom deducted R2500 from my account. This is absolutely pathetic. Where have you heard you ask a settlement on you car and pay it and then they still deduct a premium? According to Vodacom it was for my Dec invoice which should have been included in the settlement. I demanded a refund and it has been escalated its been more than 7working days with no feedback yet. If I do not get any by die end of this week I will go to the Ombudsman and approach a lawyer.