Mint Mobil Will not refund my money for phone and 1 year of service Orlando FL

For my first cell phone service I ordered a phone and one year of service through mint mobile. After waiting several weeks to receive the phone, I tried for hours to connect to their system and could not. I felt this was a sign of watch to come so I contacted mint mobile the next day, within 24 hours, that I wanted a refund. According to their website, I have seven days of free used to try it out. I didn't know there was a lock code on the phone when I sent it back so that phone was passed back to me, I took it to Best Buy and they did a factory reset. The geek squad asked me why men just didn't do that themselves… I did not have an answer of them other than mint mobile has been difficult throughout this whole return process. 

I paid $531.53 for a Samsung phone in one year of service. Samsung was extremely slow in every response so this took over a month to finally get the phone unlocked and sent back to them. After not hearing from them for a couple weeks I chose to dispute the transaction on my credit card. At that point they had my phone, I had not connected to the network to use any of the one-year contract and they would not refund me. Citibank then reversed the credit and left me hanging. At that point mint Mobile said they cannot refund my money because Citibank is blocking the transaction. I contacted Citibank and they said there is no such thing and there is no hold on my account or that transaction and there's no reason for mint mobile to not refund me. I emailed mint mobile this information and they refuse to answer me. All I need is a really good lawyer to sue them.