Actually, no it’s not how butterfly treats their customers, it’s their distributors. Butterfly didn’t sell that blade directly to you, they sold it to one of their distributors, and then that distributor sold it to you.
Also I really doubt you actually sent an email to butterfly. Even if you found the email address on the website from your regional butterfly website, it’ll still be your regional distributor’s email.
Also I’m sorry to say this, if you sent your email in the way you write here, I’m not too surprised they can’t understand you well. Btw, just a hint, butterfly is a Japanese company, if the email address doesn’t end in something like butterfly.co.jp it’s probably not butterfly you’re contacting, and you’ll need to write in Japanese if you want to talk directly with them.
And even if you and your friend have two defective blades, it’s still two out of tens of thousands, nothing to worry about.