If your phone is no longer under a FreedomPop contract then you can contact them directly and ask that they release your phone so that it is no longer assigned to FreedomPop. You will then be able to take it to your new carrier.
You can contact FreedomPop at https://www.freedompop.com/contact.htm
Only FreedomPop can unlock the phone for you free of charge.
All other unlocking services carry a charge.
You are through to JustAnswer, a question and answer service.I have given you the answer that you paid for:To get your phone unlocked for free, you can contact FreedomPop directly (I cannot contact them for you);or I can get the code for you elsewhere, but at an additional cost.Best,Pete.
Please let me know if I can be of any further assistance.