My sister had an account with her name and my mothers name on it... se did this when my sister lived with her, and nobody questioned it because Moma was living with her. But my mom move out her house 4 years ago and my sister was still in control of moma money, she paid her rent which was not that much and putting grocery in her house, a bunch of process stuff that didn't cost that much, and was keeping the rest, my sister was Paying her car payment, and other bills she had with the rest of Moma money. Well my momma is getting up in age and we all had to start pitching in, only thing is, it ended up just me after awhile, going by everyday cooking, taking her to the Dr, shopping the works, all after I got off work.... I own my own cleaning company so my schedule was flexible and the sisters said it's easier for me because I can make my own schedule. ,, So I went everyday after I got work, because my mom at the time was in the early stages of dementia the visits had to be frequent. I went everyday I stayed 15 minutes from her and I have a sister that stays 6 minutes and another one who stayed 10 minutes and still nobody went everyday but me...
Well my Mom had a stroke in February and she no longer could stay by herself and guess who she came to stay with... Well my mom money still was going to my sister and last month when I became my mother rep payee I stopped it and put the account on hold at the SS office. Well ... talking to the SS office they said she called and said she called an pretended she was moma and got the money released to her.... And kept it and haven't given her any of her money for last month!! how can i get it?
Tell them what you have told us.
As to make an appointment with them.
If it is too late for your mother to appoint you as her POA there is little you can do her to get your name on this account. And there may be nothing you can do to get your sister off of the account.
If you are now the caregiver of your Mom you may need to be appointed emergency temporary guardian. That would be you would be in charge of caring for, placing your mom in safe care, keeping records of all her assets in and out of account.
You would ALSO have to go with letters of diagnosis of incompetency in executive functions to the Social Security Office. You would show them letters from two doctors and your own guardianship papers and they would appoint you as "representative payee" of mom's social security. You would have to keep records for them as well.
All of this is exceptionally complicated. You need to know and understand how to research, how to keep records. It is complicated now by the fact that your sister is doing this without being a proper POA (Power of Attorney) it seems, and she may not be keeping records. If she is on the accounts then mom's money is comingled with hers. You may have to see an attorney to get the past malfunctioning all ironed out.
In short, what happened in the PAST is going to affect what you can/have to do now.
I would contact Adult Protective Services in your area today if you are unable to speak with or work things out with your sis. I hope they have good guidance for you and hope you'll update us.
GOOD ON YOU. You are all set.
As to sister giving back last month? I wouldn't spin my wheels on that. I don't think she sounds like she is on the up and up, and I doubt that she will cooperate. I am very relieved you are in control, but I think last month is lost. Don't mean to sound cavalier about that as it can mean you and Mom don't get to eat anything but Dave Ramsey's Rice and Beans and Beans and Rice all month, but I doubt you can do much with that Sis.
I sure wish you the best of luck.