The question is if there is a downside to disputing and trying that method before going the bankruptcy/settlement route. What's the worst case scenario? If you lose the dispute, does that make you ineligible to settle?
1) While there might be ways to phrase the dispute that wont be a straight out lie, at the end of the day the reality is all cc holder's lent money to someone on his own credit card, and the swiper did not pay back. While you are not under oath, you are in a way trying to defraud the bank Whatever you are going to tell the bank is misconstruing the truth, and essentially a lie which is a problem halachichally as well, since you are attempting to steal money from the bank.
2) If you lose the dispute, that would mean the bank did their investigation, and decided you are in the wrong. It just might make things much harder when trying to settle with the bank afterwards
3) Disputing brings much more attention to your account and connecting you to the story, wherein defaulting/settling you are one of many people that that go through that process