Welcome to the EDM forum It's the first time that i come across ONA edm's. You're using wire thickness that most guys don't even know exists. I have used Bercocut wire a lot without any problems. I'm trying Korean made wire now, must admit it's not bad for the price! You might consider CobraCut as well. Then there is the wire from Charmilles Technologies (Sw25X), good quality but a bit expensive. I'm sure they could supply you with the correct diameter wire.
Could you tell us a bit more about the ONA edm, software you use, type of jobs etc.....