It does sound as if she has mental health problems, but I would still say that your best bet is to stop leaving things outside by the doors. Take things directly to a charity shop - those bags are frequently a scam of one sort or another - and arrange for parcels to be left elsewhere. Take umbrellas inside and put them in the bath or the sink to drain. Etc etc. If you want to go further, then I suppose social services would be the next step. But she may well be getting all sorts of support which you are unaware of, so once you have made a phone call, I'd leave things as they are. Just not on the doorstep.