Mother passed away in August; sister has inherited the estate. Bank is continuing to pay bills that were automatic withdrawals,even though they have a death certificate. These company's also have copies of death certificate. Checking account is now in the negative to the tune of $300 plus. Can a bank do this? Bank is in PA?

If the companies were to to cease then no they can't continue. What are these bills for?

So when your sister took over the estate, she went in and told the bank to stop those payments ?

And who were being paid, what was it for ? Electric bill ? Insurance bill ? Rent or house payment ?