Stole Money Overpaid for an account and did not get the account

I paid 70 dollars in steam gift cards as per the seller's request for the 70 dollars account. He then demanded another 30 dollars if I want the account. I refused because I was not made aware of this before I already paid. He then offered a lower price of 20 dollars more to which I and he agreed to be the last payment before I receive the account. After I paid he did not respond back. I have evidence of our chat and of my purchase.

 

How to Report a Dispute
Please fill out all 9 questions below. You must provide proof or your claim cannot be validated.

1. Date Dispute Happened
12/7/2021

2. Are You The Buyer or Seller
I'm the Buyer

3. Total Transaction Value
$80

4. Other Parties Username
Swanson, discord: swanson#0908

5. Method Used To Pay or Receive Payment
steam giftcards

6. Other Parties Email Addresses
was not given
7. Other Parties Payment Email Address
[email protected]

8. Other Parties Messenger Username
unknown

9. Provide All Chat Logs and Additional Information Below