Bank of America gave me the run around Branson Missouri

All you have is the last for digits of an account and her SSN.  What you DON'T appear to have is any legal documentation that you are the executor of her estate or have power of attorney. Without that documentation even if you had a full account number, they wouldn't give you access to it. It doesn't matter what bank you are with.

But again you don't even have a full account number. Are you saying that you somehow know she as a bank account, but if we figure you went through her belongings, no one found a single Checkbook? A single Statement? NOTHING that shows the full account number? That in itself seems a bit strange.

Now, after this amount of time it is likely with the State's Unclamimed Property Division. There really should not be any "run around" from the State. Either they have the funds or they don't. If they do, then you will need to provide proof to them that you have a legal right to the account. Having just a copy of her Death Certificate isn't going to do it. Just be sure you are doing this from their offical site, any site that is trying to charge you money is a not the offical site.

https://treasurer.mo.gov/unclaimedproperty/

Good Luck

Once your sister died and there was no beneficiary...if the funds were not claimed after a period of time, then the funds would have been escheated to the State of Missouri - probably the State Controller's office.  You will likely have to contact the State Controller's office - or whomever receives escheated funds - and see if they have the funds.

Now, if they don't have the funds, then you may still not be entitled to the funds that belonged to your sister.  She could have had a will or trust and the funds were claimed by another person.  And no, the bank would not necessarily give you that information if you are not either a guardian for your sister, OR you lack a power of attorney over her funds...

Do you have POA or any paperwork stating that you are the trustee to the estate? Then they cannot talk to you even though you have a death certificate and her ss number. You have to have either POA or proof you are the trustee of her estate therefore you cannot acces her information. Same with the State.