Have you contacted Mark Bickerton in the UK ? He is the Tern guy over there, and would have helped immediately.
Please let me know who you contacted at Tern. I will forward it to the Owner and make sure that emails like yours will be handled swiftly and without any fuss ...
My experience is very limited with these bolts breaking, I had one instance where the frame latch was not adjusted correctly ( way way to loose ) which put undue stress on those bolts, we could however unsrew the broken part and replace with new pins and bushings
Did you get your money back ? Or a new frame ?
let me know
Thanks Thor