This is exactly what happened to me and I’m afraid it’s not good news. If the threads are stripped there’s no way of connecting the banjo bolt. Sram won’t warranty a shifter with stripped threads unfortunately. It makes absolutely no sense to me that such a critical part of the shifter, ie the threads, would be made from plastic as they can strip so easily and then the whole thing is only fit for the bin. I’ve had so many issues with Sram now that I’m planning to move over to Shimano as soon as possible. Sorry I couldn’t provide some more positive feedback!