Merrill Edge hasn’t credited cash-in-lieu after ETF reverse split (over a month later). What can I do?

I’m running into a frustrating issue with Merrill Edge and wondering if anyone has advice.

On May 5th, the GOVZ ETF underwent a 4:1 reverse split. At the time, I held 2.07 shares in my Roth IRA. Based on the split, that should have been reduced to 0.51 shares. As this would have left me with less than 1 share, I expected to receive cash in lieu for the fractional amount. However, over a month later, I have not received any cash in lieu and I did not receive the fractional shares either.

I’ve called Merrill multiple times:

* Initially, they told me to keep waiting
* After several weeks, they finally let me talk to a supervisor
* The supervisor says that BlackRock hasn’t yet paid Merrill the cash-in-lieu, which is why they haven’t credited my account
* He suggested I contact BlackRock Investor Relations, but they told me they can’t assist me directly because I don't really have a relationship with them

Since then:

* The supervisor calls me every few days to say he is still working on it and he is trying to find someone at BlackRock to help, but there’s no real progress or ETA
* I asked for a courtesy credit for the cash I'm owed, but he says they cannot do that

At this point, it’s been over a month, and there’s still no expected path to resolution they can really offer me. This feels unacceptable to me as shares were removed from my account, and the corresponding value hasn’t been returned. The total value in question is only like $20 but it's the principle to me.

Appreciate any input or advice. Thank you!