SIM Unlocking

So, I have been reading around the forums and I just wanted to know, is there any other way to SIM Unlock H811? Here is the deal. I am on MetroPCS and recently bought an H811 G4 thinking I would be able to just unlock it with a code...WRONG AF. I've been on the phone with T-Mobile for the past 4 days trying to unlock this headache. Before I contacted them I tried unlocking it through the device app with my Metro sim. That didn't work. Then I tried my sister's tmobile sim and wala temporary unlock worked but not the permanent one. So I decided to call tmobile. First they told me: "Contact the original owner" (I bought this second hand on Swappa) "And tell him to call in and request an unlock code with your email". I did that and he called and I got an email saying I was able to unlock it throughout the Unlock App. I am guessing every thing is great now because they don't give out Unlock permissions unless the phone was paid off and was on a plan for more than 40 days. Wrong again! It still comes back "UNLOCK FAILED". I tried WiFi, Metro Data, T-mobile Data and nothing! I called back and what do they tell me? We need to speak to the original owner again.....wtf? The phone is paid off and not on a plan and if you gave me the okay to unlock it why do you need his account again?

Any suggestions? You know besides the obvious "sell it and buy an unlocked one". Because that will definitely be my last resort.