I would actually tell you to tackle the problem of access to a minimum of information. As I understand it, you are saying that the voters' list does not allow you to obtain the minimum amount of information you need to be able at the very least to communicate with someone and to check whether they are going to support you or not. Revisiting what constitutes a minimum of information seems to be the solution to me, not finding other ways to communicate with people.
At the end of the day, we have the concept of consent, but I fully understand that the desire of parties to want to communicate with voters is extremely legitimate and that it may be necessary for them to obtain a minimum of information in order to do so.