Used Steam Key/Bad Support Services!

So,yesterday i,m just bought a steam gift key 50EURO for 45$ from seller Xbox, Playstation und Steam Guthaben. After i,m received the code,im immediately activated it and get error message that the code are already been redeem. Then, I contact the seller at the same times about this problem and give every screenshot i have as a proof that this code been redeem already. Got no response from seller, then i try contact support to solve this case. Support ask me to give a proof of every evidence and i give all information about this. Support ask me to contact the seller and hour by hour im waiting for seller to reply and today i wokeup got a message from seller and he asked me that i used the code on another account? Then im again try contact the support until now no response between him and seller. I have done a few transaction with Steam Pumpkin and All Good Key with smooth trades but this seller im dont know what to say and i,m now stuck.:sweat:

@DunnBiscuit

Hey, please can you send me your request number so I can directly check it for you?