FWIW, my friend was able to have her name completely removed from the membership rolls, and she was never visited after that except by random missionaries who didn't know who she was. Nobody she talked to in the church told her of the existence of this process, even when she was directly begging to be completely forgotten and never bothered again, which makes it sound like a conspiracy theory or an urban legend, but it exists, and it works. My guess is they had to set it up to comply with a law or fulfill the terms of a settlement. You'll have to look for it online, because I forgot the name of the process and who helped her with it, but any of the online ex-Mormon support groups should be able to point you in the right direction.