GMG appears to be having stock/inventory issue with COD: AW, which often goes in and out of stock. We have report of people having issue receiving a key even though the game was stated to be in-stock and allowed to be purchased. YMMV whenever they are back in stock.
Alternative deal is DLGamer for $53.99 after coupon DLG-TAPVKEYC
Note: As of 11/8 at 8 am Pacific the GMG $49.99 offer is no longer valid. In case they bring it back, you can check here.