rent re council propery for deceased parent.

[blue84]

Handed keys back to council over 6 months ago. Received no contact from housing re payment of rent during the period after death until keys handed back. Gave them my address and phone number.
So assumed that they were not going to pursue it.
Received a utility bill today clearly addressed to council so rang up council about this.
They are now saying there is a balance outstanding on the account. A housing person is calling me back tomorrow.
Should I just accept that there is a rent arrears and pay it or should I complain about them not pursuing it themselves.
Ironically parent never paid rent whilst alive.
Thanks for any tips.