On exactly what grounds do you want to sue them for?
The fact that you were a victim in check fraud is unfortunate. I can guess that it had something to do with you receiving a check from someone you don't know who said to cash it and send them money back through Western Union. But this does not remove your obligation to your other bills.
Now, you said that this happened in January/February yet you didn't see any late charges until recently. Then they did not Repo your car until September 30th, at least 7 months after this happened to you. So just how is giving you 7 months to get caught up not working with you? How long do you think they should have given you to get "caught up"?