I have been wrongfully accused of Financial Abuse of the Elderly. What can I do and how do I prove I am innocent?

You should consult with a defense attorney.  Hopefully, this can be resolved by communicating with your neighbor and her family.  But, you could be subject to criminal or civil liability for abusing your elderly neighbor by financial exploitation or misappropriation.  Financial abuse consists of the misuse, misappropriation, and/or exploitation of an older adult’s assets – monetary and/or material (e.g. real property or personal possessions).  Your neighbor stopped giving you permission to keep her change; when you continued to keep her money without telling her, you could be found to have misappropriated her monetary assets.  You could face a civil suit for recovery of the money she has “given” you, as well as damages.  You could  also face prosecution for the crime of larceny by conversion. 

You were clearly authorized by your neighbor to use her shopping money to accomplish duties she assigned to you, and at first you were expressly authorized to keep a specific portion of the money (i.e., “the change”) at the conclusion of your performance.   But, it is at issue whether you illegally converted her assets on each occasion when you continued to keep to keep her money after she stopped giving you express verbal permission to do so.