The IRS says,
If it's been more than 8 weeks since you filed your amended return and you haven't received your refund, please contact a customer service representative by calling 800-829-1040. From outside the U.S., call 215-516-2000. TTY/TDD: 800-829-4059.You can also use Where's My Refund? tool on the IRS website.
According to the IRS you can get information about your refund 72 hours after they acknowledge receipt of your e-filed return or three to four weeks after mailing a paper return. (You cannot use Where's My Refund? for an amended return.)
You will need to provide the following information from your return to identify yourself.
- Your Social Security Number (or Individual Taxpayer Identification Number)
- Your Filing Status
- The exact whole dollar amount of your refund