Is it unlawful for a collector to harr the children of a deseased parent with no estate or insurance,will?

our mom lived alone and paid her own bills, and all we did was contact ALL utilties to be disconected, All agreed to Write-Off her debt because there was no estate, no will, no insurance, 7 months later, were still getting collection notices, weve gave death certificates several times, does the state of Ohio have a law or statue that states a person is not responsible for another persons debt unless a contract was made jointly? by the way both parents are deseased and us kids had too cover the cost of the funeral.