Liability of Family after death of Debter

Dear Sir/ Ma'am, My father passed away in the june of this year leaving behind a host of debts, mostly without a co-signer. He rented my mother's property from her for a pharmacy on which he took a stock loan, that is what we've been told which had the principle value of 10 lakh which was extended to 12 Lakh. Right after his death the manager of his branch told us that we are liable to pay the loan as it is a property loan over the land and my mother's signature was on it and bullied us into paying some amount right then. a new manager came at his place soon after. we later find out that we were lied to and my mother hadnt signed anywhere and the it wasnt a property loan. then the new manager froze our bank accounts, my mother, mine and my little sister's without giving us notice and when we went to talk, ill behaved. We've been told by all that we are not liable for the loan but the bank has been harassing us. Also my father's car was also bought on a loan which was also not paid. we paid it off first. There was no will and none of us three has inherited anything as our house is my grandmother's, another land of my father is under another loan, and this land with the shop is under my mother's name. What are we (Mum, SIster and I) liable for? Is the car an asset of my father's estate after being paid off by us?