Help with G2a

Is it normal that I've been waiting for a response from support for days?

I already contacted the seller, and they referred me to G2A support.

I pre-ordered Resident Evil from a seller and only received the code in the evening, even though the game had already been released that morning. At midday, I contacted the seller to cancel the order. They told me to wait until I received the code and under no circumstances show it to them. I did that and contacted the seller again the next day. Suddenly, my cancellation was rejected, and I was referred to G2A support.

What can I do now? I already bought a new code because the wait was too long, and I made sure beforehand that I could return the code to the seller… and now they're saying that's not possible, but I do have a right of withdrawal, don't I?

I paid directly with PayPal. Can I just open a case with PayPal, or what should I do? Does anyone have any ideas?