My iphone is locked to orange and i need to unlock it to t-mobile

I've got an iphone from cex 2nd hand and orange. I can't get the phone unlocked by orange because i'm not the original account holder?

Orange and t mobile are the same company

I unlock form http://iphonejailbreak-unlock.com, you can unlock/jailbreak your too and price is only $19.95 this is only lowest i found.