NCO Financial System (student loan debt collector) - can they take money from a bank account?

NCO Financial letter, regarding student loan, states "We are in the process of reviewing your financial background to determine if you have sufficient ets to pay..." I reside in North Carolina. Can they take money out of my bank account? There is no judgment that I am aware of. The only et I have is a bank acct with less than $1,000 to cover my bills--except for an old car, worth nothing. Should I close my checking acct? or keep minimal balance? I'm hanging on by my fingernails financially as it is, self-employed, living hand to mouth. I don't want to close my bank account, but should I? Thanks for any help from someone who knows the law in North Carolina on these matters. Appreciative of any information or advice from someone with knowledge and experience. thanks!