Yet another controlling response from the troll on here.lol Telling you "you need to do this or that, or Don't do this type responses.
I would set a time frame for the rent to be brought to current amount owed. I would send this information certify mail, as well as posted on the door. This T seems to have lost her ability to maintain the cost of the property. But that does not make it the LL problem, unless the LL wants to subsidize for the T.