Forza games critical reward-system bug has been enduring for months. Over hundreds of Forza fans complained about this on the forum of Forza official site. They urged Forza to fix this problem as soon as possible, and provide all their redeemed rewards, including cars and credits, back to their own accounts, yet the problem still hasn’t been resolved entirely.
Source: N4G PC Faulted Reward System In Forza Games Has Been Bugging Many Players For Months