Struggling to get a refund from Vodacom

RE: EC-218H-21X3HF: Account number: I***/9. I had a contract with Vodacom. (1) Vodacom cancelled the contract and reallocated the number to someone else. Vodacom, through their lawyers, HP Attorneys, forced me to pay the remainder of the contract (R12000) for a service that they were not providing. (2) It so happened that I ended up overpaying the balance of the contract by over R5000. (My statement clearly shows this. I did request a refund through their legal specialized division, and they promised to resolve the case in 7-14 days. Now 14 days have passed, and the case is not resolved. I am a grieved and hurting customer. Regretting the day I ever signed a contract with Vodacom.