Where are you, UK or USA or elsewhere?
Most stores in the UK offer some form of live food on the counters i find. Usually bloodworm or daphnia. You could try gettinga bag of these and put them into the tank when the lights go off at night. You might find your eel is more nocturnal, so he could be finding scraps of food at night but not during the day. My armoured Bichir (different fish i know) feeds only at night mainly.
If you can't get out to a shop theres always eBay. Wherever you are people will ship products out to you, or deliver to your door. There are options available.
Do you know for sure if your eel is definately NOT eating at all? Don't want to sound patronising, buthave you ruled out hes not just being out competed for food from another fish that perhaps has the same food source? Just trying to think of things.
