How do you settle a Acknowledgment of service and consent to petition for an estate settlement.

Please accept my condolences on the loss of your mother. Without seeing actual documents, it's not really possible for anyone to tell you exactly what's going on. However, it sounds like the check that your mother received was intended as the final distribution to her from your aunt's estate, and that the Acknowledgment you mention was supposed to be her statement that she understood her interest in the estate had been fully satisfied and that she was okay having the executor of your aunt's estate (or administrator) discharged from that role and released from liability with regard to the estate. If my guess as to what your mother was sent is correct, the executor or administrator of your aunt's estate is filing a Petition for Discharge (assuming it was a Georgia estate) and now needs to have the sheriff serve the executor or administrator of your mother's estate with notice that the Petition is being filed, since your mother passed away without signing and returning that Acknowledgment. If your mother's estate has had an executor or administrator appointed, then that person may be able to sign the Acknowledgement on behalf of the estate and return it, which would avoid having to have notice served by a sheriff. But I really think that you (or the executor or administrator of your mother's estate, if you aren't it) needs to have an attorney review the situation and anything that was sent by your aunt's estate's representative, to be sure what is going on and whether signing the Acknowledgment is the right thing to do.