National Security & Fire - Incompetetant

In 2010 my parents took out a service contract with National Security & fire then known as Chubb Secuity. They surprisingly took out the contract on my mother's name who, at the time was unemployed (only they know how they can go into contract with a person who is unemployed). My dad was currently earning an income, having his own business. Last year August my dad passed away and payments on the account stopped. National Security & Fire starting sending letters of demand and even handed the account over to a debt collectors being NuDebt Management (PTY) LTD. I explained the situation to them , that my dad has passed away and that this was my mom's only source of income and that she is now reliant on a state pension but they would not listen to any reason and demanded the full amount outstanding which at that stage was R 2,776.77 . I then took it upon myself to make arrangement to pay the account off and an agreement of R400 per month was finalised. To date I have paid 5 x R400 = R2000.00. Up until last week, I have still received an e-mail demanding the amount of R2,776.77. I have sent e-mails to Gretta Mokoatle (JHB-SOUTH Credit controller) and she told me there is nothing she can do seeing that the account has been handed over to the debt collectors. NuDebt Management (PTY) LTD tells me that the account was handed back to National Security & fire after my attorney has sent them a treathening letter and advising them that we will sue them for harrassment if they dont rectify the account. I have been sending e-mails weekly with proof of payment begging for an updated statement but no one responds. My last e-mail dated 10 May 2018 was sent to 08 recipients......no one responded. This morning I sent teh same e-mail asking for assistance. these are incompetant people. Don't use them. They broke into my sisters house, the alarm was activated and we got to the house before armed response could get there. They got there about 20 minutes after us. By that time the ********* were long gone with her tv.