Just looking through your chats with them, I may have missed it but the IP issue is a major one. I see you responded that you only used your cell, but based on their rep, I find it hard to believe they are not spot on with this. Not trying to take sides here, just my opinion on what you posted and I read. Did you travel at any point where you flew from Chicago to FL that would explain the 2 location IPs the same day or use a VPN in FL?
Not going to comment either on the tax side of things, but I think a few of the suggestions of getting a wire and proving it is you is a good one, esp if you can get them to do a $25K wire or similar and then use BTC/LTC after.
Word to the wise...and this is ignoring what either side claims here with IPs - don't let anyone use your wifi or phone to bet. Just not worth it. Big tool they use to detect multi accounting. If I have friends over for a game, use your own phone to bet...my wifi is off limits.
They are not the only shop to monitor IPs. I was gone on a trip to Europe last summer for 2 weeks.
BetOnline locked my account on the 2nd day over in Italy (first day passed, then they must have locked it quickly). Had to jump on chat and provide a boarding pass and proof of a return flight back to the US. They opened it back up at that point, but took some back and forth to prove it was me. Honestly, good they do that to protect accounts as well as themselves.