AUDIO HC 15

Firstly, you need to be sure the voice coils have been fried.  Test with a multimeter to get confirmation.  The reason I mentioned so its not your amplifier that has stopped functioning for some reason :uhoh:

Once you have determined that it is your subwoofer ,then get online to see speaker repairers closest to you so you can obtain quotations for the work.

Good luck with it and hope you determine the culprit and then take steps to rectify it. If it is your amplifier, then go shopping for another one, mate!

HC? That's gotta be Resonant Engineering...old sub you got there. . When they 1st started, they had a few lines out and HC was one of them. As DrBoom stated, check both coils with a DMM. If you don't have one, they can be had for 5-10 bucks. But a regular household battery is another great way to check voicecoils on a sub.