What is happening when Where's My Amended Return? shows the status is: Completed?
This means your Form 1040X- Amended Tax Return has completed processing resulting in a refund, balance due, or no tax change. This timeframe also means all correspondence related to the processing of your amended tax return has been mailed to you.

https://www.irs.gov/filing/individuals/amended-returns-form-1040-x-/amended-return-frequently-asked-...

Try calling the IRS