Electronic filling was rejected Feb 2021. March 2021 I mailed my 1040X. 09/15/2021 and still no record my return. What can I do?

Was rejected because of dependant/stimulus oversight. Unable to amend online, mailed documents. Over six months and "where's my amended return" doesn't even acknowledge my returns existence. I dont think waiting hours to speak with an IRS person will help, what should i do?