Legal heir

My father recently passed away due to Covid.Before his death he was working as a collection agent from last 3 years in one credit society but the agency was on mother's name.Before his death from last 3 years there was no issues everything was fine company made huge profits and my father used to get customers for them but now after his death the owner of the credit society has started bugging us saying there is some issue in account tally of customer,there is difference of some huge amount while account tally of customer account closure,some customer documents are missing and so on all blame on my father and asking us to help. As per him the company was dependent on my father majorly and the owner himself doesnt have much knowledge he himself admitted he is owner just for name sake(only for signatures approvals) everything was managed by my father.Although there were few more staffs who did account tally but he is helding my father responsible for everything.Now what can be done in this case and are we family members liable for this?