[ohio] Booked A Flight. Airport Is Asking For 300 Extra Dollars And Won't Offer A Refund.

[Resolved Issue] Location: Ohio. So I just got off a 1 hour phone call with United Airlines who called me to let me know something about how they actually ran out of Economy seats and had to bump me up a seating class. A lot more was said, but that's the short of it. I already paid for the ticket, and now they are saying they want 300 dollars more, and refuse to refund it. I asked multiple times, even asked to talk to a supervisor or manager about it to try and escalate the issue because (in my opinion) it's absurd to suddenly rugpull a customer like that for more money without offering a refund.

I already called the 3rd party website I bought it from and they just redirected me back to United. They keep telling me my options are losing the money I already spent, or paying another 300 dollars for it. The 3rd party site I used was "tarifasodeal" if it helps any. The ticket said full refunds for cancelations made within 24 hours, but United said "Your ticket does not come with that" or something along those lines. Is there really nothing I can do? This feels like a genuine scam.

Small update: They keep calling back every 5 minutes. Exact same number. I haven't picked up since I felt it'd be a waste of time as they were 100% hellbent on not upgrading me for free nor giving a refund. I'm thinking of accepting the call but only if I have some new questions to actually make any progress on either of those goals.

Final edit: It was a scam yep. At least I found out quickly. Don't trust tarifasodeal