How should we get big companies to listen to our complaints?

Where I live (Draper, UT) Verizon Wireless is terrible. I will often drop calls, have text messages that fail to send, and above all I have horrendous data speeds (100-400 kbps, on occasion reaching 500-600, rarely over 600, if requested I will provide links to Speedtest.net results). One Verizon's website it says that while on the 3G network I should be able to expect at least 600 Kbps, up to 1.4 Mbps. It's a constant problem both in my home and all around the Salt Lake valley. I have an iPhone 4, and have confirmed my problem with many other devices, including my father's Droid Charge (both on 3G and 4G LTE), my neighbor's phones (on occasion), grandma's iPhone 4, and my cousins' iPhone 4s (plural iPhone 4, not 4S). I have called multiple times to complain about the issue, filed multiple trouble tickets, and each time I have received the same response of "We tested the area and have found nothing wrong. All of the towers in the area are operating normally, and there is nothing we have to do." This is obviously not the case, ut doing the same thing over and over again and expecting different results would put me in the definition of insanity. TL;DR Verizon is problematic for me but won't do anything to fix it. Reddit, what can I do to make them listen to me?