Wondering why they would want you to not have your address on the envelope? Do they believe the certified letter will be refused? If it is refused, there will be a record that your mailing was refused. I must say, I honestly don't believe the lawyer gave you sage advise. Why put someone else's name on the envelope? If you were to go to court and produce the certified information, you have to admit deceit. If you are that concerned they would refuse the mail, go and file against them in small claims court (if you are under that financial ceiling) and then they will be served by a professional or the sheriff.
Insofar as they paperwork, I would imagine that they have standard paperwork provided to their customers and are required to keep their sales files. They would have to produce that in court.
In order to file a claim in small claims court, I don't believe you have to the paperwork. I'm not a lawyer, but I think the purpose of small claims court is for the court to hear the evidence, not that you have to produce evidence when you file.
Your state law specifically says that it is not on the plaintiff to actually prove fraud just that the defendant "possessed the tendency or capacity to mislead or created the likelihood of deception." I believe you have a case under the statute with regard to an "unfair act or practice". I would send a certified letter that states you have repeatedly requested your paperwork and they have declined to provide you with copies. You have been in touch with an attorney who says they have a legal obligation to provide you with a copy of your paperwork, if requested, and have 10 days to do so (to be picked up in person) or you will file a claim under the NC UnfairTrade Practice Act.
Again, I'm not an attorney, but I think you have a case.
Sharon