When I send an email and people reply using microsoft office, the email goes to someone else in anothe country with the same email address in hotmail. How do I resolve this so my emails come to me

I replied to an email that was sent in Microsoft Office.  The person replied back but I did not receive it.  Instead it went to someone in England who has the same email address in hotmail.  How do I fix this as it is happening frequently

liz