Poor legal department service

I lodged a claim against vodacom in July disputing their claim that I owed them after I had settled the account 6 months before. I sent the lawyer at FNB all the communication I had had with vodacom with the last email being the confirmation of receipt of the proof of payment I sent after settling the account. After that my number was changed to prepaid and to my knowledge I settled as requested. 6 months later I get SMSes and threatening intimidating calls that claimed Vodacom had been telling me to pay and I refused. I was puzzled and angry that they **** about contacting me and I contacted FNB legal services. The legal advisor seeemed to be helpful until Vodacom lawyers sent their settlement amount. I explained to the legal advisor I was prepared to pay the debit amount and nothing else because I had settled the account as they demanded. I got no response from her. I periodically sent emails asking for follow up and nothing transpired. Then on the 15 December 2017 I called. The legal advisor simply told me I am liable for all that is demanded. I do not think she made effort on my dispute.