Prospects Never Answer Their Phones or Respond to Emails

I work in a market where I'm lucky enough to usually have a cell phone or direct line to decision-makers, which is great...BUT I'm at the point where I simply cannot get prospects to answer their phones or respond to emails. This will be the third consecutive year where I've covered the same territory and there are still target prospects that I've never once been able to connect with.

I've used a local dialer to mask my area code in the past, but I've felt this puts a bad taste in the customer's mouth and the conversation usually begins on a "fuck you for being deceptive" note. Any creative or new ways that I should try instead?