My redemption code claims it's already been redeemed.

I just bought the "Get to Work" expansion pack for the sims 4 [PC] and when I tried to redeem the code it says its already been redeemed.

This is the first time I am inputting it into the system. Why and how is it redeemed if its a fresh code, I just bought?

I purchased another expansion pack "Discover University" also for the sims 4 [PC] and it worked fine.

Please help me I'm so confused.