I amended our return on Feb 27th 2019.When I check the Where’s my Amended Return Tool says they have no record of return even though the IRS says they have received it.

Where did the IRS say they received it?

On the phone. They are very reluctant to give me any information but did say they received the amended return

could just be a processing delay.    Once they open the envelope they can log in the return.  however, after that, it goes on to be processed, which can be weeks after envelope opened.