I coudn't received mail from outside domain such as Yahoo, Gmail ,etc

Dears,

I have an Exchange server 2013 Enterprise edition , I can sent to outside domain such as Yahoo, Gmail , But I couldn't revive from out side domain ? 

For that reason, We are  configured Office 365 to fix it , now is fixed after enable office 365 , 

BUT, Now I want to decommission  my Exchange sever 2013 on office 365, and keep only my Exchange 2013 and remove office 365,

 So, the first I need to mail flow working fine (Send & Receive mail with out any issue) , Then I will make decommission of Office 365 

Thanks in advanced