Mental and finantial harassment by my Aunt

My aunty has been demanding money from my mom(her sister) and me from last few years. At first her husband was violent and was asking for money, we kept helping them now and them due to emotional reasons but both my Aunty and her husband are cons. They dont respect us but my aunty has a bank loan and she keeps harassing us for providing monetary help to her to pay off their bank loan instalments. We would keep refusing but she keeps calling and coming to my home and keeps harassing, requesting, emotionally blackmailing till we help her. It is really very hard on us and our mental health. This has been going on for years and we see no end to this. Aunty has a daughter and we fear not going legal with this as she will have to take the burns of the deeds of her parents, she is too young and dependent. We are stuck, don't know how this can be stopped without causing a havoc. They have properties they can sell to come out of their financial debts but they keep demanding money from us suggesting the bank will take their mortgaged property and they will not be left with anything. How can we stop this mental and harassment ?