To your question 3, the answer is no.
Even if there are FDCPA violations, which is by not means certain, (which would take too much time to explain here), the action to collect the debt, and your claim for and FDCPA violation are separate. A creditor can still sue to collect a debt even though you may have an FDCPA claim. The creditor still has the breach of contract claim for you not paying the debt. The FDCPA claim is related to possible collection violations.
Since you don't really elaborate on where you are in the process or the lawsuit, to difficult to elaborate further.