If my mother has a legal court appointed guardian who is not properly looking after her affairs, what can I do to get a new guardian?

I'm afraid this may take an attorney (check with your state bar association to see if there are any who would do this low cost or pro bono (free). First, start with social services and see if they have advice on how to go about challenging the court decision. They may have other ideas. You will likely need proof of wrong doing. Good luck,
Carol

Do you have a copy of the court order?
If not, then you need to go down to probate court (which is the court that usually handles guardianships/conservatorships) and get a copy of the order. It should state the mechanism for changing or challenging the order. You will have to file to try to be appointed the new G/C for her or to change G/C's.

Just out of curiosity,why wasn't a family member appointed?
Usually the judge defaults to family unless there is just cause to go "outside".
If there is family friction, they can appoint an outsider to manage the elder's affairs and that person will be paid to do so out of the person’s assets.

Once a G/C is established I bet it would be hard to go back to a DPOA situation for an elder.You really need an attorney who is experienced with G/C - one thing you can do when you are at the courthouse is look at other G/C orders (this is usually all public, open-document for the filing page) to find the names of other attorney's who are used by the court to be G/C and contact them to represent you.
They will know the system for your mom's area - this is invaluable.Good luck.

Can a court appointed guardian be removed immediately after proof that person commited perjury against a family member ?