Hearthstone Arena 11 - 2 instant loss BUG

Hello,

So I was playing Hearthstone arena and was 11 - 2. I got connected to my last player and we started playing. It was around turn 2 or 3 when the game instantly showed the message of reconnecting to a game and it got me connected to another different player MIDGAME. So I was angry at first because it was the last game of my arena, but still managed to beat the newly appeared opponent, however after the last win I got returned to the main menu which was strange. When I got to my arena page it showed that I lost my last game and got 11 - 3 as my final score which it wasn’t because I just won my last game. So how would it be possible for me to lose a game if i got reconnected to a new arena player and won my last game. My last opponent history shows 2 last players which were “Last opponent - Linmi#2726” “Current opponent - twilightrain”. I’m kind of frustrated and sad because getting 12 wins on arena is no joke and I feel I got completely robbed.