you get no acceptance e-mail for mailed returns.
if you are due a refund you can check the WMR site
https://sa.www4.irs.gov/wmr/
or call the IRS. However, it is possible your return is at the IRS in an unopened mail bag.
If you didn't do so, in the future if mailing your returns, use a tracking service so you'll know if the IRS got it.
