Demands made for payment but not willing to provide details.

My dad had an account that was apparently handed over to vericred. ( Details will be supp**** directly) I received a call this morning regarding this so called unpaid account, however when I asked for the details I was told this cannot be provided to me as I am not the "responsible person" How can I assist in verifying or seeing that the account is paid if you want me to be involved but refuse to send me details of anything. Surely that's ********* and I would not be comfortable in assisting to sort such an account out WITHOUT receiving the supporting documentation which shows the account handed over, communications being send before additional charges were added, as well as proof of payments that have been done already on this account as I am sure and according to path care statements certain payments have been made.