Deceased MIL final return was filed but no irs response

I submitted (by mail) the final tax return for my deceased Mother in Law. I have no response from the IRS. I don't know the date I submitted. I cannot get any response from the irs. A refund is due. My wife is the personal representative (executor)... We sent Form 1310 along with the court letter indicating my wife as the estate representative... Any ideas or help ?... Thanks!... Richard