There really is no point to respond to those letters. You will not get your meds back, and if anything they will monitor you more closely since in the eyes of the law you did break it. You are ok for now, but with several letters and you answering them, you are bound to be headed for trouble. The personal use law only applies when you have the meds on you and you are crossing the border such as Mexico or Canada not by mailorder. Then you are in a whole new territory such as customs and postal inspectors who can be tough and do enforce laws. No confusion, just read the DEA page on importing meds, it states this.