Attachment 6297
Try us at filabits.com. We have samples of NinjaFlex in 1.75mm and 3.00mm diameters. You may also have better luck printing with SemiFlex...it's a little more rigid, which will aid feeding, but it still offers a high degree of flexibility. We carry this as well.
Another option to try would be SainSmart's flexible TPU. They're a cheaper alternative.
If we don't have the filament you want, be sure to voice it on our NEW FILAMENT VOTING PLATFORM.
Use code 3DLOVE to receive a 25% discount (expires 6/27/15).
Happy sampling!