Default [Q] Sim Unlock for Foreign T-Mobile One

So I bought a phone on Ebay that was originally purchased in Hungary. I wasn't sure whether I would be able to unlock it, so I called T-Mobile Customer Support, and they said that it was no problem that I was buying it through ebay, and that I would just need to request an unlock code when I recieved it. However, when I went into the Tmobile store, I was told that I couldn't request an unlock code, and that the Ebay buyer would need to request one from his carrier. So I asked the buyer, and he checked with his carrier, and they said they would only unlock it if he brought it in physically. He doesn't live in Hungary anymore, so that's obviously not a possibility. So then I went online and found this site, htcunlocker.com, and bought a code. It still hasn't arrived, and if it doesn't arrive in the next couple of days, I'm going to request a refund. Is there any other way to unlock my HTC One? I don't mind paying up to $30 or so, as long as the code actually works.