I more than sympathize; not only do I have the same problem (and, in addition, my actual renewal has not been acknowledge --though money taken-- for three months) but also, I am the Membership person for Pilchuck Audubon, representing Snohomish County and Camano Island. So, I get to see the membership roster and "changes" every month for our area.
National Audubon has had difficulties with their membership tracking for quite a long time now. I don't know why they are having so many difficulties but I suspect there may be several "groups" responsible for different parts of the whole membership process and are, perhaps, using different pieces of information. This shouldn't happen but that kind of thing is often the case in non-profit organizations attempting to keep administration costs low.
I'm not apologizing for NAS, because, believe me, I'm also very frustrated, but I can actually understand some of the problems. Local chapters have expressed some frustration with this issue and we are (just) starting an effort to see how we may be able to help make the process more effective.
In the meantime, do contact Chapter Services at National. You may not get a satisfactory answer right away but it will help to draw attention to the problem. You can also contact me at <membership...>; please use the Subject line "NAS membership questions." It will help to gather information on the extent and kind of problems. I'll try to reply (probably not with a solution; I have few of those) as soon as I can but it may be a few days. Still and all, we are all trying to help the birds persevere and, we hope, prosper.