First put in for a change of address and make sure you put in a forwarding address with the post office.

https://www.irs.gov/forms-pubs/about-form-8822

Then call the IRS :

If accepted by the IRS use the federal tax refund website to check the refund status - https://www.irs.gov/refunds

If over 21 days since being Accepted by the IRS and the tax refund is still Processing you can call the IRS and speak with an IRS agent concerning your tax refund.

Call the IRS:  1-800-829-1040  hours 7 AM - 7 PM local time Monday-Friday

When calling the IRS do NOT choose the first option re: "Refund", or it will send you to an automated phone line.  

So after first choosing your language, then do NOT choose Option 1 (refund info).  Choose option 2 for "personal income tax" instead.

Then press 1 for "form, tax history, or payment".   

Then press 3 "for all other questions."

Then press 2 "for all other questions." 

- When it asks you to enter your SSN or EIN to access your account information, don’t enter anything.
- After it asks twice, you will get another menu.
Then press 2 for personal or individual tax questions.
It should then transfer you to an agent.

Or you can contact your local IRS office. See this IRS website for local IRS offices - http://www.irs.gov/uac/Contact-Your-Local-IRS-Office-1 or call 1-844-545-5640 to set up an appointment

Or you may want to contact a Taxpayer Advocate in your area. See this IRS website for Taxpayer Advocate in your area and a toll free number - http://www.irs.gov/Advocate/Local-Taxpayer-Advocate