I think it will be a waiting game

If you change the growing media, the roots that had acclimated to a different environment will be less able, or unable, to thrive in the new setting. The older roots will die, but the plant will eventually put out new roots that will function in whatever environment their exposed to (within reason, of course). If you've mounted a potted plant, you'll know what I mean. The old roots that were never exposed to light, nor (for all realistic intents) air flow die off, but new roots grow in after a few months and will be properly suited to the new environment.
Don't give up, just yet

It looks like there are some bright green happy new roots!