1) They can put you on a no-hire list, since in employment at will, any employer is free to decide who to hire and who to not hire, and there is no right in or to a job.2) However, the cannot reduce your pay for work you had already done (e.g. prior to giving notice) unless there had been some written agreement stating they could do that. Otherwise, they had to pay you at the rate you'd been earning and if they don't, you could sue them for the money they should have paid, but did not (for example: sue in small claims court, as your own attorney or "pro se").