My experience with the carbon blacks is similar. While tuning up the first set, the e string broke. I replaced it with one from the other set that I bought. The set sounded great for 2 days until the c string broke. I sent the company an e-mail suggesting they might want to check this out but I never received a reply.
Hi guys, I have seen right now these further comments.
the carbon blaks are not in the market since January 2018 (Martin taken the place there) . I am sorry to hear that you has a such problems. Bariukish, you told that sent us a mail a no one answered you? I trust totally you however it sound strange: my collaborators MUST answer to people that place complains. And this take the first position over money, over orders. Maybe the mail went in the spam? who knows.... Please mail me there:
aquila@aquilacorde.com. I will do my job. Mille grazie.