I got the same rifle this past month and identical part broken. Took a good look at the design and material, it,s quite cheap and poorly made compared to the rest of the rifle which is half descent. You didn't post back what the final result was and I surely wouldn't be happy to just have them replace the part with an identical one. That would be unacceptable seeing it would most certainly result in a repeat failure. I could machine a custom aluminum feeder but no time to do so. My next option and simplest would be to get it repaired, sell at a loss and not ever purchase a C-Tac product. :/
Word of mouth in this day and age can make or break a business in the blink of an eye. Been there done that.