There are similar complaints in this thread. This one reply says jaxx switches address automatically at certain time intervals, and often has problems syncing, so balances don't get displayed correctly. If that's true there's a chance your coins might still be accessible.
https://forum.z.cash/t/restore-t-adress-jaxx-wallet-warning/8225/34Don´t worry about the changed address. The address changes automatically at certain time intervals. Nevertheless, any previous address is still valid and can still be used.
I have just looked in my wallet: I am also missing some coins. But that´s not because the change of your adress. Jaxx currently must have a problem when retrieving the blockchain, so not all coins will be displayed. You can simply enter your t-address at Zchain11 and then you can see that all your coins are still there. Hopefully, Jaxx fixes the problem quickly!
Try importing your jaxx wallet's seed into mycelium's android wallet and see if your coins show up in it. According to this post the two wallets can use each others seed.
https://www.reddit.com/r/BitcoinBeginners/comments/5xt8m6/my_12_word_seed_from_jaxx_isnt_showing_my_balance/Jaxx follows BIP 32/39/44, so Copay (mobile and desktop) and Mycelium (Android, probably iOS) can restore the Bitcoin wallet from Jaxx.