Ok, so this is the third thread about the same thing.
Let us suppose there is a manufacturing defect and it has affected all the arms from a certain batch onwards.
Other than refund the value of the part, there's not a lot could be done until the manufacturing issues are resolved. There may not be any healthy versions of said parts in stock yet.
This is obviously bad news, but given this issue was raised around the beginning of May, perhaps the first batches of healthy arms are already making their way. It's coming up to 3 weeks.
Maybe Corally could confirm what's going on.
Have they returned your emails yet?