I’m curious… how did you manage that? How were you ever able to use your expansions at all? There’s no way to log into the LM with two different emails that I’m aware.
However, merging your products might be possible. I think it was clarified recently that there is actually no transfer fee involved with either BFD3 or expansions. So, at the very least, you should be able to transfer your expansions to the other account and manage one account from then on out. Though, as you can read below, you’ll see it might not be an easy process.
This user explains how he ultimately was able to transfer all his products to someone I’m assuming bought his stuff.