Do they have a Facebook page, a Twitter feed, or any kind of social media presence? If so, post a complaint on their FB page and then get on Twitter and tweet every robocall they make with sarcastic side comments, and see how fast they respond. This was how I got the Red Cross to stop calling endlessly, in an effort to get my stepdaughter to give more blood (and more! and MORE!).
If they don't (or if you don't do social media), try sending them an email here: email@example.com and tell them that you have been attempting to reach them in an effort to get them to take you off their call list without success. Tell them if you are unable to order supplies because you can't reach their customer service. Hint that you're considering taking your business elsewhere (even if you're not, that should light a fire under them, if their CS is any good at all.)
BlessedLife, do as I did, leave Liberty to there doom! ;)
I switched from using Liberty to Diabetes Supply Center of the Midlands (DSCM) and ended my frustration and suffering. Now with DSCM, I have my own rep that contact me the way I prefer (by e-mail) and check if I need supplies, since my insurance require that I approve it each month before they can ship it to me. Here is their site: http://www.diabetes-supply.com/home.asp
They are located in Omaha, NE. Hope this helps!
I used to order all my supplies from them. I switched to medtronic for my supplies after Liberty drove me nuts by not answering my calls or keeping promises to ship supplies or call me back. Medtronic is no picnic either, but at least you can get someone on the phone and, most of the time, they keep their promises to ship or call back. Sometimes, the worker involved even provides superior service, well beyone what you would expect. I order my testing supplies from Byram Medical and have found them to be very reliable.
I have never had trouble getting thru to persons at the 800 Liberty numbers. Not sure why you could not. The number I have for pump supplies is 1-800-467-8546 x45081. Have you tried that number and extension? The trick is to get to the correct dept that deals with pump supplies. And way back when I started with them, I asked them to stop the robocalls and they did. I do get postcards but those are easy to deal with.