if you e-filed on 4/7 within a few days you should have gotten 2 e-mails. the first would tell you it was successfully submitted. the second would have said the IRS accepted or rejected the return. if you didn't get these e-mails you didn't successfully submit the return. in that case, if you don't owe, as finally determined by the IRS, there is no penalty. if thre is a penalty and this is your first time filing late, you can request the IRS abate the penalty (not the interest) by submitting a request when returning the penalty notice without payment except for any interest.
