Millions have received tax refunds and stimulus payments. However, many have not yet received them. Those who filed tax returns in February and early March before the cutbacks due to the pandemic seem to have received their refunds and 80 million got their stimulus payments on April 15.
The IRS is not currently processing any mailed returns.Since the IRS is currently not taking any phone calls, all you can do for tax refund information is to track the status using the IRS tracking web site: https://www.irs.gov/refunds
You track the status of stimulus payments using this IRS portal: Get My Payment
See these Q&As for more info: https://www.irs.gov/coronavirus/economic-impact-payment-information-center