What providence that I saw this AB.
I also grabbed a ych from BrokenVocaloid back in July 2019. After a long period of silence, I went looking for ways to contact the artist, and ended up getting directed to the SebastianMorgensen FA account as an in-between contact (for some reason). Still, I tried giving both accounts a note asking the status of the commission in February 2020. Only SebastianMorgensen got back to me, asking for info like my Ref, Paypal, the YCH link, etc.
I provided all of that, and didn't even get a confirmation that they had read the note before getting total silence again.
Definitely avoid BrokenVocaloid and any account that handles their business.