Do I need Guardianship to make decisions for my mom?

Your mom (or both parents?) live on their own? In the community or in AL? Are you nearby or are you doing this from a distance? I'm not sure why the OoA would be contacting you mom monthly, our case manager only reassesses biannually. From my understanding their role is to be an advocate for their client (your mom) and to facilitate any services she needs. If mom says she doesn't want to change her caregivers then that is who they will listen to. What specifically is the problem? Can you address those concerns with the caregiving agency?
The finances are a different matter, if she is no longer able to handle bill payments then there are a few strategies you can try. You can set them up as auto-pay or pay online, you can have them redirected to your house or go paperless. If she is overspending then you can ask her credit card company to lower her limit and you can move her saving into investments she can't access as easily.

Ooa calls mom every other mo. Mom has her good days, but bad out ways good. Her financial is a mess,,,im bured out.

Mom is in and out. The aides ive had i want them gone,,they're not doing there job. Mom said she agreed. Then OOA called mom,she said no,,im ill myself and i need good care for mom.

Is your mom still considered competent and resisting what you are trying to do for her? The POA only allows you to work with her to carry out her wishes, to make her comply against her will would require a guardianship. Of course you can't get that unless she is incompetent... catch 22. I'm with Jessie, we need a little more info here as the post as is doesn't seem to make sense.

Guardianship is usually reserved for fairly extreme cases, such as when someone is incompetent and didn't have a POA set up before it happened, or if someone is out of control and combative. What do you want to do that the OA says you need guardianship? Is your mother no longer competent to make her own decisions?