Looking for feedback on what I would assume would be a common situation for salespeople. I have no signed agreement. Figures adjusted for simplicity. I start a position with compensation as a salary plus draw. No wording or specifics if draw is to be "recoverable" or "non-recoverable".

Some months my commission levels are $1,500. I still only receive draw amount of $1,000. Some months my commission levels are $800 and I still receive draw amount of $1,000.

At the end of the year, I terminate my employment. My draw for the course of the year was $12,000. My commission level for the year is $10,000.

Employer seeks to recover the $2,000 shortfall.
1. Is it legal?
2. If it is legal, is my only defense such that we have no signed agreement specifying if the draw was recoverable or non-recoverable?
3. Can they threaten to hold back my 401K balance when I seek to roll it over?
4. Again, no signed agreement between myself and employer on the status of the draw or implications upon termination. Only have a letter from employer at time of hire discussing position: Relevant wording from letter is:
"Your compensation will be X salary + X draw for three years. You will be able to go off the draw at any point during the three years."

Thanks for any feedback.