I filed my 2019 Fed return by mail. The IRS rec'd my check, but say they never got my return. Should I contact them? send a copy? Or file electronically thru TurboTx?

Summary:  I have 2 issues:
1)  How is best way to get my 2019 return to the IRS.
2)  I am motivated by NOT receiving the 2nd COVID-19 stimulus check (i.e. $600), and PROBABLY not receiving the current one (i.e. $1400)