FNB, how they are NOT helping me

I am on pension and realise towards the end of last year that I am in trouble, I've decided to sell one of my properties to get out of debt with FNB and others, all went well till I was informed by FNB that they misplaced the title deed to my property. As a consequence, delaying the sale process with several weeks. I was hoping for this deal to will be done by now for me to settle all my Debts. my question is who is in fault, why do I get harassing phone calls on a daily basis from FNB threatening to hand me over, this deal can easily be delayed by 2 to 3 months if not longer by a fault on FNB side. What about the interest on my overdraft, the sleepless nights, do a 70-year-old pensioner still have to face this tension and harassment on a daily basis due to a FNB fault? Is this the way FNB treat pensioners after banking with them for more than 30 years? I need some help on this matter.