Bondic is not a glue (per the FAQ on their website: notaglue.com )
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and on slippery plastic will likely result in even weaker bond than any other adhesives. The commercials are misleading (as are all "As are all as-seen-in-TV miracle product commercials). For high-stress slippery-plastic parts I have never found an adhesive that will provide a lasting fix. Welding (like you did with the soldering iron) would have been my top choice. But that didn't even work? Another possibility would be a mechanical fix (if that even lends itself to the shape of the broken parts). Drill holes in both parts and install (glue) in a brass rod to create a mechanical connection.
There are also various types of CA glues and primer specifically designed to bond hard to glue materials, but again, I don't think those will give a lasting bond for this specific problem. Microscale sells such a glue, and so does Cool Chem (cyanopoxy).