Jessa,
I am sorry to say that IMO, none of the so-called reef safe medications are consistently effective. I certainly would not bet the lives of my fish on any of them. This is just another reason why quarantine before placing fish into a reef aquarium should not be considered optional. You probably would have avoided this situation if you had quarantined.
I recommend keeping a cycled quarantine tank running at all times.
Fish will generally continue to eat normally until the infection becomes advanced. Unfortunately, you have painted yourself into a bit of a corner. Sorry, but there are not any easy, convenient ways out of your situation. There are some things that you can try, but the odds are not in your favor that they will work. The only I can suggest that MAY work that is easy to do is to feed the fish garlic soaked foods for several weeks. A powerful UV can help, but it is not a reliable cure either.
The only treatments that are consistently reliable require treatment in a separate aquarium. Copper, hyposalinity or the transfer method are the only treatments that can be depended on to work. Maybe you should consider getting a large food grade Rubbermaid container to use as a quarantine tank. Just add a heater, some PVC pipe for hiding places and something for water circulation and biological filtration. BWT, no ich treatment works on every phase of the parasite. Even the best treatment takes time to work by interrupting the parasites life cycle at one stage or another.
Terry B