Settling of outstanding Account

Bad!!! My mom has an account with them for many years and she was always a good customer. When she become the age that she needed to go to an Old Age Home she decided to get me a secondary card to buy the things she needs or when one of our family members have a birthday then she tells me what to buy to give on her behalf. She had a credit of almost R15000 and I had them previously cut the credit to R2000 that is managable for her. After the last 2 birthdays her health deteriorated very quickly and she was moved to Frail Care and obviously we had much more expenses regarding medication and payments toward the Old Age Home. So I (the 2nd cardholder) cannot afford to pay her Foshini account too, but I made them an offer of R100 to pay off the account, but obviously they did not accepted this offer and only told me that this purchase was done after the account were settled in the first place and they are going to hold me liable for this account and hand it over to attorneys. Now, not only are they clueless, but they also under estimate my intelligence too. They outstanding amount currently is about R1100 and theymade huge mistakes, because why in the world would you still give a 80 year old woman a credit of R15000 on a state pension and never scrutinise the account details to see what the age of that person is and to keep on increasing the credit after they were phoned to ask them to keep the credit at R2000. So after I send them and e-mail explaining everything + a video of her current state they have no compassion for that and they just need their money regardless of the fact that she was a good customer all these years and now to threaten me to pay the account while I have bearly money for food and we still have to pay anormous amount to keep her in the Old Age Home. I think they are rude and disgusting and their employees need to be more considered instead of thinking that everybody they talk to is stupid or clueless which I think is jus the opposite.