I believe that their technique is to force arbitration based upon the "mandatory arbitration" clauses in many credit contracts. If they are enforcing such a clause, they schedule an arbitration, and you fail to appear, it is all-but-inevitable that they will get the arbiter to rule in their favor. At that point they will take the arbitration decision to a judge for entry as a judgment, and you would be in the position of trying to dispute its validity.

Assuming that there is a mandatory arbitration clause, you can check with a consumer lawyer in your state to see if there are any court rulings which would render an arbitration clause unenforceable, given the facts and circumstances of your case and language of your credit contract.

Their post-judgment remedies would vary by state. Some states, for example, don't permit wage garnishments. The normal paths toward collection are garnishment (wages, bank accounts, other liquid assets) and execution (seizure and sale of items of personal property, and possibly real property).