How IRS contact me?

[Mfmash1]

Hello,

i was an international students from 2016 till 2020. I used TurboTax to file my taxes for 2019 and 2020, and i just knew that I shouldn’t have used TurboTax. Will the IRS contact me and demand to return those refunds? If so, how will they contact me if i moved overseas? 
I am planning to amended tax return, but just wanted to know if the IRS has been trying to reach me or not. 

[ee-ea]

The IRS only uses mail to contact  people.

[mfmash1]

Thank you. In this case, since i was international student and i filed my tax through TurboTax and i moved overseas, how do i know if IRS has contacted me?what could be the consequences if they contacted me through mail and I didn’t respond because I already left the US??