1. I understand you're pissed with Jet. I also feel that you have no understanding of technology. So don't go around making these accusations that it was a inside job. Instead use this energy to chase down Jet till they return your 90k miles to you.

Also, I would suggest both of you change your email and other account passwords right away.

2. You don't get any notification for accessing the website or (I think) even for a booking unless you specify the email id during the booking. Besides the first thing the hacker would do is change the email id in the profile section to get all notifications him/herself. So change your passwords and go to the profile section and ensure the email ids and phone numbers are correct. If they have been changed make sure you note the new info before replacing with your info.

3. I don't understand what a local site is in this context. It's a redemption and has to be done through Jet's website. Doing it by selecting different language and country options doesn't change that it's still the same Jet website.

Also any redemption made through your account will still show up in your account details section. So you have some information to start with already. Not that you can do any real investigation yourself beyond this. But keep following up with Jet till you get your miles back.

Most importantly change all your passwords, use 2 factor authentication wherever possible eg: Gmail etc. and make sure that the profiles in your accounts have your correct info - esp. the name, email and phone.

And keep sharing your experience here... it would be a good learning for everyone.