After you file

I did not get any notice from the IRS but they just cashed a check from 8 months ago I sent for a tax extension. In the meantime I had wired them payment (because they told me they needed the money or I could get a penalty, even though it was their fault it was taking so long to cash my check). So I put a stop payment on the check and then 8 months later the IRS cashes the check (stop payments only last 6 months). What's worse is that they don't have any record of this payment!? I am freaking out... how can they cash my check without having any record of it? The check had my SSN on it. Are there any tips on who to call and what to do? I have called the main number for hours and nobody has a solution. Please help!