I just thought of this:
I don’t know how your soldering skills are, but maybe you could try to order a new driver from Haikelite and swap it with the current (probably) faulty one? It might be just as expensive as the shipping costs in case of returning it, but you might end up with a working flashlight instead.
In this topic: (Flashlight Manufacturers and Distributors on AliExpress (new layout)) you can find a link to an Aliexpress shop that seems to be the “official” Haikelite shop, or at least a shop that offers seperate Haikelite drivers. Just send them a message and ask if you can order a HK05 driver.
As far as I can tell Haikelite doesn’t have an own website through which you can order. Another option might be is asking Neal from Neal’s Gadgets if he can provide one, since he also sells Haikelite, but experiences with Neal/Neals Gadgets do vary a bit though.
Or maybe another member here on BLF might know of a way to directly contact Haikelite?!?