You have 6.35977462 BTC @
Address: 17oYuaq5LYp4aEgx7ShnLk94PhV3WM1qLS
https://blockchain.info/tx/96d59c9a52d2931bcba954354c763eec5a66835f617a2830fe3a7cddedb7120e
txid: 96d59c9a52d2931bcba954354c763eec5a66835f617a2830fe3a7cddedb7120e
Output index 0
You have 0.28966627 BTC @
Address: 1kS4YvpoEz3PSoL4uqCSZhHyzTkMZ618n
https://blockchain.info/tx/b3381d7534cddd0c33d341a738d0002379eb6e1c14837928e842c7779362f9f4
txid: b3381d7534cddd0c33d341a738d0002379eb6e1c14837928e842c7779362f9f4
Output index 0
You have 9.24199431 BTC @
Address: 1PzGwvF95UpA12a9ac7KAaR4C2BzsL5Ush
https://blockchain.info/tx/fccdd481d31ed559f44507625e1fc9974b67e3c733e6e31df34fee313f08d331
txid: fccdd481d31ed559f44507625e1fc9974b67e3c733e6e31df34fee313f08d331
Output index 0
Total comes out to 15.8914352 BTC.
That is exactly what your balance said BEFORE the erroneous transaction, AND all three of the above inputs show on blockchain.info, blockr.io, AND insight as being "Unspent"
Your coins are there. Just tell MyTrezor to "forget my device" and then reconnect your Trezor. It should re-scan the blockchain for transactions and this time it WON'T find your erroneous transaction.
Edit: Please make sure you have your phrase written down as a backup.