I've found it's best to wait a couple of weeks and then try again, as usually they recycle codes. I've used the same code more than once using this method but it may not work for all the codes.
Your account shouldn't be flagged just for using codes, the problem occurs is when you shift domains between multiple accounts as I've seen so many people get caught out for here and I have little sympathy for them. As long as you use the codes in good faith you shouldn't have any issues no matter how many you use.