horizon artic tank

I have an IPV D2 and an IPV D3 both have an ARCTIC HORIZON on them. Suddenly I am unable to find coils for them!!! First did they stop manufacturing the coils for them? Can I use other coils than the ones they manufactured? Also, if I can't get coils anymore what tank should I purchase to...

I have 2 horizon tech artic tanks. One is slightly different than the other. It doesn't work. I can try to switch coils and other parts and it won't work. One coil from it will work with the one I think is real . How can I find out more about telling a fake from the real ones.