My Gamertag is CoyoteFranck
I didn't get any code for the 2 operations "discount gamerscore", although the 2 reduction codes I received were used.
The Xbox Support told me to post here.
Code for first Gamerscore (amazon/xbox) Offer (EQHB-LKF5KT-DGVSY7 to obtain Forza Horizon 2) was used close to the 30/08/15
Code for second Gamerscore (micromania/xbox) Offer (+AD318KC to obtain Gears of War) was used on 29/11/15
I have no possibility to phone support for now (please send code using my contact adress defined on my gamertag)
Thanks to solve this problem.