Discover Credit Card Complaint

Discover Credit card department,

Rewards Illinois

Discover has an offer where you refer a friend and they give you a $50.00 reward if the friend sings up. I referred a friend who got accepted but i never received the reward. On contacting the customer service i was told there was some error in the prior statement as i had received - rewards which was then deducted from my current statement rewards without specifying it in the statement. On further questioning, they did failed to show me how much of error was present my previous statement.