If you were giving the right to use your elderly aunt money

[Ottos]

If you were giving the right to use your elderly aunt money as long as you took care of her and her bills, can a new court appointed guardian try and get money back from you since now they consider her incompetent.

 

[Proserpina]

If the guardian can show that Aunty was incompetent at the time she gave rights to do anything with her money, yes - it's possible.

 

[Betty3]

Who gave you (or whoever the person was if you're not talking about yourself) the right to use aunt's money if the person took care of her & paid her bills? Was this handled through the court system or legal document? Was the person a court appointed guardian?

The answer to your question though is it's a possibility - depends on exact details. (ie if aunt incompetent, when diagnosed, etc.)