I have seen many complaints over time regarding problems with saved searches and saved sellers; either users are unable to add or delete new searches or sellers, or users are not receiving emails, or users are receiving emails from "zombie" searches that cannot be deleted.
If you are not receiving emails about your saved searches, there is likely little you can do aside from making sure that your email provider is not blocking emails or characterizing them as spam.
If you cannot rely on emails from eBay, you may want to consider third-party options. Google "automated searches eBay" for some ideas. Most of those will offer a limited number of daily free searches which can be split up in various ways.
