You'll probably have to excavate the epoxy like a "moat" around the stub of the wire and as a jeweler, I would use a ball-shaped bur to do it. Dremel might have something you can use. Check your local jeweler of hobby shop.
Then, you're gonna have to get some solder into the stump and that's gonna require a sudden short blast of heat so as not to fry the insulation on the coil. You're gonna be taking a chance of ruining the pickup if you try this.
If you were successful with the solder it would be easy to remelt the solder while shoving a wire into it for the join-up.
If it were me, though, I'd own up to what I did and send it back to the manufacturer for them to remedy the situation. They've probably done it before and it would be worth the extra cost and time to get it done right. If you fry the pickup on your own, you're out the cost of the entire pickup.


