Close account for a deceased

My mom passed away on the 26th of July. On the 27th of July I emailed Woolworths her ID and death certificate. I also phoned and was told by the consultant that I needed to email it again as nothing was on system. Which I then did.

Last week I get a call from WFS requesting payment on her account. I explained and they again asked me to email the death certificate (3rd time).

Today I got ANOTHER call. Still nothing on system.

Is there balance protection on her account? Can I settle it on her behalf?

I don't want to continuously be bugged by collections.