The last I checked, ethereum is a decentralized platform and you don't need just one platform to access your coin as long as you have full access to your private key which controls the wallet, so I think you are really making a mistake somewhere because or you made use of a centralized wallet and might not be able to access that coin until the wallet support the coin maybe then or even in the future, but if you have access to your private key, then you just need to visit any wallet and import your key.