There's a contradiction in your information.
If your Aunt died with out making a will, she died intestate. That means her estate is divided according to the rules set out. In which case if your Aunt had surviving siblings then the estate is divided between them and you are not a beneficiary, unless you are the surviving child of another sibling?
Then you say that your Aunt did in fact make a will?
Can you clear that up first?
Edit to add:
Also in regards to the SW issue, there's only two ways this would apply.
1. Your Aunt did not fully declare her means to SW when she was alive.
2. Some payments continued after her death, if SW weren't notified quickly to stop the payments.
Item 2 should not be very much money, it's refunded to SW once probate is completed.
Item 1 is a bigger issue and there could be a substantial clawback.