Try getting a leviathan weapon instead and use that to get you through second coil and your next step can be to get the rowena + tonestone weapon and high allagan gear. Or if you don't plan on raiding, get neither the atma nor the leviathan weapon and just not worry about it. People cancelling their accounts over atma is pretty extreme. It's an optional quest that didn't exist until last month. It's not required to progress in the main scenario or anything important. If you cancel your account over anything, it should be the very frequent lag and disconnects from the server, not an uninteresting optional quest that was added.