No emails from them that are in the spam box. I have no problem receiving their support email before they stopped responding.
Don’t know how they can hack a phone which has the Google Authenticator that is not even turned on.
If you are 100% sure that your email/mobile is not compromised, then it is the fault of the exchange. I guess the hacker has made use of some vulnerability within the website, which would allow passwords to be reset even without the email confirmation. Or it can be an inside job (but the chances are even lower). I can see that you have already got the funds moved from the exchange wallet. So it may be good, if you post the details about the exchange. Let them respond to it.