Bad service from FNB

I settled my credit card debt last year through one of the lawyers FNB had handed over my account to. After paying it off 8 months down the line I have had three different lawyers who apparently FNB have handed over my account to aswell. The one that was calling me last year is MBD and they were the ones who called me with a settlement of R13992,45 which I paid within 7 days. I have no access to FNB because I’m told they can’t see my account since it’s been handed over. I paid through a settlement offer given to me by MBD. Now I have very rude lawyers harassing me everyday. Despite my explanation that I have been getting calls from three different lawyers they refuse to send me a direct number I can call to get FNB to update their system. And clearly FNB is not updating the other lawyers they handed me over to. This lady Nonhlanhla from GLA has been harassing me saying I didn’t pay and I have explained I have sent the paid up letter to different lawyers who continue to harass me everyday. My issue is why don’t FNB update systems after payment and why do they hand over one account to more than one lawyers who in turn don’t talk to each other or report back but instead be rude to customers. If FNB can release a paid up letter why don’t they also update the system as paid up. I have all the proof that this account was paid up